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Jim, The parallel-sided free bore length on the 49-10 is 0.252" and does not include the "chamfer" or step down from case mouth. All chambers that I know of have a 45-degree step-down from case mouth to throat. Ignore that little distance, it is a given. Throat starts with either parallel-sided freebore of X diameter and Y length, or it is all leade, e.g., the .458 WinMag has a very wide leade at beginning that tapers down over a +2-caliber (over 1 inch) run before rifling is fully engaged. So throat length is the sum of free bore length plus leade length, only those two items. Yes, the free bore length of the 49-10 is only about 1/4" long (about half-caliber), and the total throat is about 1/2", which includes the leade of 1.5 degrees plus free bore length. And, the free bore diameter of the 12.7x68mm Magnum/49-10 is a generous .502", .002" greater than bullet diameter. This does not hurt accuracy in such a big bore, and it will assure trouble-free extended dirty work under field conditions. Also it will allow trouble-free field use of cast lead bullets of .501" diameter. WE BAND OF FORTY-NINE-TENNERS: THE THREE MUSKETEERS | |||
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Hey RIP, Yep I knew that but was lazy when I posted the data; I'd noticed a misskey in the QD data and corrected it but failed to rekey everything in my post. It's corrected now. Jim  "Life's hard; it's harder if you're stupid" John Wayne | |||
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On the question of max velocities with copper bullets and long throats, I hope to shoot some water jugs in August. I can check out Woodleigh 450 grainers at a probable 2600 fps. A chronograph will be used, of course. Will anyone be doing testing before then? While pondering short throat options, I wonder if AccRel cases can be neck-sized and used in a 49-10? The shoulder of the AccRel begins at 2.14", so it would probably fireform and jump forward to 2.16" of the 49-10. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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RIP formed his 49-10 cases by fire forming 338 Lapua Magnums so no sweat with a CRF based rifle. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Thanks, Capo, I suppose I was thinking more about whether the case could be used 'as is' and would it function close to 100% without a non-hunting, fireforming interim? +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Hey Tan, Gotcha... I think it would be safe in a CRF rifle, not sure about a PF but then I don't own any PF rifles. I have to ask...I thought I'd heard that the QC 500 AccRel brass was delivered as cylinder brass rather than formed/FLR brass. Did I hear incorrectly? Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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No sir. Qc brass is fully formed opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Thanks Jeffe, my misunderstanding. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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I just saw that this thread does not have the nice copper rifled bullets recovered from an elephant and a hippo. Muzzle velocities of both is estimated as slow, 2000-2050 fps.  The left bullet from a hippo the right from an elephant skull. Both are Barnes 570 grain TSX fired from a 500AccRel. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Dang that's cool And good engravings too opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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I've finally been able to testfire my 500AccR. Some loads are listed at AmmoGuide. It's a sweet little cartridge. In the notes for the loads I've noted that the rifle has a 1.25" parallel free bore throat. Haven't been able to test for bullet recovery and rifling marks yet. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Rob H posted this-- and they seem to work great.. little imperial wax in neck and on shoulder.. then trim http://www.midsouthshooterssup...em.asp?sku=002858693 opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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i was able to testfire some Woodleigh RoundNose Softnose Weldcore bullets in some sand today. Here are a couple of pictures  There are riflings visible. The bullet tunred inside out and penetrated a few inches of sand. Velocity was 2486fps. Here is a second bullet  Riflings are a little clearer in this picture. Again, the bullet only penetrated a few inches of sand and turned inside out. The Woodleigh 450 grain Roundnose weldcore was at 2537 fps muzzle velocity. This is a little step forward in showing that copper bullets are able to handle the 1.25" freebore at least to 2537 fps. But for brass bullets we will need a shorter throat. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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So now come the big questions, what should owners of 500AccRel's do? How should they prepare hunting loads?  1. Several 500AccR affecianados to band together and have a copper CEB MTH bullet set up and run off at about 430-450 grains. This should be functionally similar to the GSCustom 450 grn HV. Costs for the CEB would probably be less, and access in NorthAmerica would be easier than the SouthAfrican GSC. RIP's experience with the 49 calibre is promising, indeed, and I could be tempted to forgo a rebarreling if I my rifle would shoot such CEB's the way RIP's does. The nose should ideally be kept to 0.70" in order to feed in standard magazines. The biggest downside on this is that accuracy with a 1.25" freebore and such a bullet is an unknown. Back in the days that when freeboring was a more common calibre enhancement tool it was considered risky when people went over 2 calibre freebore. Sometimes it worked, sometimes not. However, organizing such a bullet run can also be used in tandem with the next option. 2. A Reamer could be adjusted that could be deposited with someone like McGowen Barrels. Are there any 500AccR reamer-owners out there who would consider this? I would recommend a 0.25" freebore. I've been told that Manson Reamers will do such a modification fairly inexpensively and quickly. Maybe Buffalo has something to say about this. Maybe even McGowen Barrels could do the reamer adjustment if Jeffeoso was on board with it. This is out of my expertise. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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It’s been awhile since I’ve seen a photograph of the 450gr .510 GSC HV bullet but I seem to recollect that it’s a fairly short bullet with a slightly curved base – more like a radius edge on a flat base – rather than the traditional BT that many of the HV bullets have. So bullet wise – if your typical shooting length is: 1) <350yds go with the CEB FBHP bullet style… For the FBHP bullet style – I recommend you use RIP’s and Max’s nose shortened .395 caliber CEB FBH bullet style for your .510 caliber, just have Dan upsize it to .510 caliber and shorten or lengthen the base to meet your weight goal. Dan modified the .308 caliber FBHP nose length so that the bullet would seat properly in the .375 Ruger case and function through the Ruger M77 magazine (Max’s .395 Ruger Max). 2) >350yds go with the CEB MTH bullet style… For the MTH bullet style – I recommend you use the .416 caliber 350 GR. LD HPBT-STD MTH V11 bullet as your base style, have Dan upsize it to .510 caliber and shorten the nose to function through the Ruger M77 magazine with the STB seated at the case mouth. As an FYI… Dan computed that the FBHP bullet style would have fully met my w/i 350yd maximum hunting range but that the MTH bullet style offered me better trajectory numbers for ranges beyond 350yds. So as I desired the ability to practice at 400yds and 600yds I opted to go with the MTH bullet style (though modified to include the FBHP banding) so that I hopefully could become very proficient with drop and windage projections from 300yds to 400yds…or as we now know from RIP’s testing…from approximately 245yds to 400yds. And .500 AccRel finish reamer wise… If an existing Manson reamer is to be modified – send it back to Manson…they’re the professionals in this arena with a quick turn around and very nominal charge to modify an existing reamer. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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gents, see my reply in the other thread.. we have folks testing the throat for effect .. lets await the results? as for minimum length, .510 at a minimum ...and i will remove all references to milsurp loads to keep someone from blowing up a gun if we go with the shorter throat ... which might be 500AccRel mkII opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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I understood that Buffalo and gunsmith confirmed that their brass bullets were shearing. they went ahead and ordered a new barrel and a modified reamer. Are there other tests going on? I am going to slowly work up some loads for copper bullets. Unfortunately, my 'easy' bullet recovery is to shoot a shoping bag full of sand. It kills the bag 'dead right there' but as the pictures show above, the bullet is so disfigured that it is impossible to evaluate the bullet for more than a 'yes/no' question, are engraving marks visible? So far, up to 2537 fps, the answer is Yes. My next round of testing can raise the velocities some more. The rifle is shooting a little slower than estimated, but that is inherent to safely testing and building up. I figure that a max load is still a long way over the horizon.
I wouldn't remove the loads, just label them "fired with rifle with 1.25" freebore". I've done that to my AmmoGuide uploads. What is the point of a .5" freebore versus something shorter like .25"? A primary concern in a rifle is accuracy. You know the cliches: "There is never 'too much gun'" but also "only accurate rifles are interesting". By the way--The Ruger Hawkeye Alaskan platform has worked very well. the rifle is 8 pounds naked, 9 lbs with scope et al. It handles nicely from a bench though once or twice the recoil put the rifle and my arms off of the rests and on to the table alongside the rests. maybe too relaxed? maybe too tense in arms? Whatever. On a skype call my son called me out on a question of whether I "enjoy" shooting the rifle. He said that my grin gave a lie to any potential 'Yes" answer, but he did allow that it could qualify as enjoyment in the same way that longdistance runners enjoy a run. At least the rifle lets you know when it's fired. I am undecided as to whether a 8 oz mercury reducer would be a help or a hindrance. Would 9.5 pounds be too heavy? Maybe. But I have more testing to do. And I need to wait for the black and blue to resolve after months of no shooting. it's sort of like calluses and guitar-playing. There's always a little shoulder bruising after a long lay-off from shooting. +-+-+-+-+-+-+ "A well-rounded hunting battery might include: 500 AccRel Nyati, 416 Rigby or 416 Ruger, 375Ruger or 338WM, 308 or 270, 243, 223" -- Conserving creation, hunting the harvest. | |||
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Sorry for being grumpy last night I am waiting Ulrik results to know better what length. Why at least a caliber? A couple reasons and excuses. And I don't like short throated big bores. You see a really good example in the Lott vs winnag opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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I’m not quite sure which thread this should be posted to…so I’ll just pick this one and let things fall where they may. There have been some interesting discussions regarding milsurp bullets and length of Freebore in the 500 AccRel. Anyway, I created a 500 AccRel cartridge in QuickDESIGN using the data that Jeffe has provided (though I’m presuming a 1º30’ throat angle) so that I could use it to compare with other modern and historical cartridge chambering data – at least two per caliber… Ok…the closest cartridge comparisons to the 500 AccRel are RIP’s 500/338 Lapua Mag (12.7x68 Mag, 49-10) – both based historically off the .416 Rigby Magnum case, both with 2.65” case length, both with 20º shoulder angle, and with only very minor differences in the base-to-shoulder and neck length – and Michael’s 500 MDM. Of course there is the .510” vis-à-vis .500” bullet diameter difference. So here’s the comparison: (Using the case mouth crimped at lower edge of upper band and with the 0.050” belt width of CEB BBW#13 brass bullet belts, we have the following…) The upper belt on the CEB BBW#13 brass bullet travels before: Cartridge – Engaging the Rifling – Arriving at Bore Diameter: 500 AccRel = 1.2148” – 1.4248” 500 MDM = = 0.3397” – 0.5647” 500/338 Lapua Mag (12.7x68 Mag, 49-10) = 0.2167” – 0.4458” And recovered bullet comparisons at almost identical MV:
So what do we know? The .510 caliber CEB BBW#13 fired into water filled milk carton @ 2320 fps MV gives no rifling marks and the banding is completely abraded smooth. The .500 caliber CEB BBW#13 finishing shot @ 2380 fps MV fired through both shoulders of buffalo and recovered from the ground underneath and even though the bands are almost completely abraded smooth from impacting and penetrating the ground the full rifling engraving is still clearly visible. My conclusion is that the brass BBW#13 reaches sufficient velocity somewhere in the 0.875” distance difference between the Freebore of the two chambers that causes the banding to be completely abraded from the bullet rather than the rifling engaging and engraving the bullet. I suppose this is one of those times where you can draw your own conclusion. Again sorry for the length of this post. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Jim, Good post. I was a disbeliever when I first heard about the free bore jump allowing enough velocity to shave the brass bullets by skidding into the lands. Copper, gilding metal and washed steel jackets must have enough friction to grab and start spinning before they start shaving. Now can anyone convince jeffeosso that the 1.25" freebore is excessive?  There is only about 0.75" length of parallel-sided, full bearing bullet shank on this about 2.50" long bullet, the 750-grain/.510-caliber Hornady A-Max. If you seat only 0.25" of the shank length inside the case, then only 0.5" of remaining shank length is above the mouth of the case. Even this bullet is going to have to jump about an inch of free-bore plus leade before it begins to engage, in the 500 AccRel. Ain't no sensible reason for that.
Just consolidating from the other thread redundant to this one. Jeffeosso may answer here, about the dummy 50-cal round that requires 1.25" of parallel-sided free bore!!!!  | |||
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Notice that the blacktip-AP milsurps need less than caliber-length freebore, shown here in 500 A-Square. It is crimped on the existing cannelure, but could be loaded longer, with no crimp, and there is lots of room for that with a caliber-length parallel-sided freebore. Read the ruler. Guess what? That Hornady A-Max is loaded out about as far as possible, and yep, you guessed it, caliber-length, parallel-sided free bore is more than enough for that too:  | |||
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Here is that obsolete GSC 450-grain/.510-caliber HV. Gerard has redesigned it since I used it to take a cape buffalo with one shot through the heart. That bullet did not open up, tumbled through the heart after passing through the shoulder bone:     Above MV was 2654 fps, non-opener hit buffalo at about 80 yards, insurance shot into dead buffalo opened from anout 10-yard range. Here is another one recovered from dirt berm at 100 yards, though MV was 2835 fps:  I think the new GSC has a bigger nose hole, just guessing.   | |||
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RIP, I don’t believe any of us perceived there would be an issue with the brass construction BBW#13 bullets in Jeffe’s 500 AccRel but obviously there is just enough difference between the properties of solid brass and solid copper bullets that the brass banding will not engage the rifling while copper banding will with Jeffe’s Freebore specification. We do however know that the properties of the solid brass bullet’ banding engrave just fine when the chamber has less Freebore. Hopefully Ulrik’s and Hatting’s tests with the different Freebore specifications in the two barrels will resolve the issue. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Jim, I have lots of experience in shooting brass bullets in greater than 1/2-caliber-length, but no more than 1-caliber length, parallel-sided free bore. 500 Mbogo and .395 Tatanka are prime examples. Even the S&H brass NonCons (.395/310-grain) at 2800 fps engraved beautifully, and they have the minimal bearing "shark-gill" type bands. If any bands would shear those would!!!:  The greater bearing surface on the S&H .395/330-grain FP solids of brass also at +2800 fps MV worked great too:  This band pattern (minimal bearing and shearing prone if any would be) on a .510/535-grain S&H brass FP solid works great in a 500 Mbogo or 500 A-Square:  The 535-grainer has too big a meplat, over 70%, so I am still working on getting a rifle to feed it reliably. Maybe a Wby Mk V straight stack ... 500 A2 500 Mbogo 500 Jeffery  I am sure a throat that is 1/2 to 1 caliber-length in parallel-sided free bore will be no problem. Use free-bore diameter of .001" to .002" over bullet diameter for .500 or .510 calibers. Use leade of 1.5 degrees. No waiting for answers needed. Proven many times over already. | |||
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RIP, I have no doubt that 1/2-1 caliber freebore works as it should simultaneous with giving great accuracy; it has certainly been proven with the 49-10 as well as the long range accuracy Dan is noting in multiple calibers. Personally I think something between 0.375" and 0.450" freebore would resolve the brass bullet banding abrading issues while accomodating every bullet currently manufactured in .510 caliber. I think Jeffe hit on the solution the other day, it's time for the 500 AccRel MkII (or perhaps the 500 AccRel ST) so that pure hunters can use brass as well as copper bullets. S&H bullets...those VeloHex NonCons are definately nice bullets and perform as well as they look. I don't recollect the exact shape of their current FN Solid, but I do think a FN Solid using the same shape as the VeloHex NonCon obviously sans HP with a radiused 67%-68% meplat would be a great performing solid as well. The major problem that I see with the 535gr .510 S&H FN Solid is that the nose sorely needs a nice radius to the edge. The meplat radius would help with feeding and within mass straightline penetration but the 70+% meplat needs to be reduced to 67%-68% to optimize penetation and feeding. Otherwise the S&H bullets are darn nice looking and they perform as well as they look. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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RIP, Did you ever shoot the 450gr .510 GSC HV bullet at 300yds? I'm just wondering how it's trajectory would compare to the 430gr .500 CEB MTH bullet. Also thinking that CEB FBHP at same weight would work pretty well at 300yds... Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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I need to get myself a mini-lathe and put a 13-degree BBW bevel and radius on those solids, to reduce the meplat. Heck, might as well turn some of those into NonCon hollowpoints too, while I am at it.  Regarding 300-yard shooting with 500 Mbogo and 450-grain GSC HV: Nope have not done it. Here is the max load with that bullet. 2654 fps with filler was more accurate than this 2835 fps load:  Above was with .500"-length, parallel-sided freebore. Below was 500 A-Square with .587"-length, parallel-sided freebore (lengthened by separate throat reamer) in my misguided days when I thought I needed such a long throat for target bullets and milsurps, and I was calling a long-throated 500A2 ".510 JAB":  I would not use brass bullets in that excessive rifle throat. Will stick to copper. Keep freebore down to less than caliber length. Bore-diameter length of parallel-sided freebore, or less, is good.  | |||
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Anders wrote to me this morning that he have asked David Manson to chenge the reamer to the following specs: Cartridg: 500 AccRel Length of freebore: 0.250” Length from neckchamfer to Bore Diameter: 0.4748” Throat Angle: 1º30’ Freebore Dia – 0,511 Dont you think that will work???? | |||
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It is too short but I would approve it. Look at the 458 winmag vs lott opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Perfect.  | |||
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Jeffe, According to the pundits over the past 40+ years Winchester did everything wrong with the 458 WinMag. Look at the modern 450 Rigby and it appears the 458 Lott was done correctly. Even the modern 9.3x66 Sako with their old school zero parallel freebore and gental throat angle is only 0.6697" chamfer to bore length... Ulrik, Bases upon Michael's and RIP's .500 caliber chamber specifications I believe you will be very happy with the new chamber specifications. How are you going to mark your barrel? 500 AccRel ST? 500 AccRel MkII? Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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I would ask that you mark the reamer and chamber 500 AccRel ST 0.25 or something like this. I also wouldn't go less than .510 .. but its not my money opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Ok... I believe I can the issue regarding the parallel sided freebore for the 500 AccRel to rest with QuickDESIGN. If my observations are correct, the two non-bore riding traditional construction .510 hunting bullets with potentially the longest parallel sides are the Woodleigh 570gr SN and FMJ. With the following information I can give you the absolute-minimum parallel freebore required for the bullet to chamber in a .500" bore/.510" groove dimensioned barrel chambered for the 500 AccRel: 1) Maximum diameter & that specific location on bullet. 2) Distance from base to point where bullet drops below maximum diameter. 3) Distance from the bullet base to the bottom edge of the crimp groove. 4) Distance from the bullet base to top edge of crimp groove. 5) Diameter of bullet just above the top edge of the crimp groove. 6) Distance from base to point where nose Ogive begins. 7) Diameter of bullet where nose Ogive begins. 8) Length of exposed lead core for the Soft Nose. So who is up for providing this information ASAP? And if someone wants to provide the specifics for another bullet I can create a QD bullet to provide the same information... Perhaps for that very long AMax bullet that RIP showed the picture of? Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Ulrik, Hatting, Tanzan, RIP, and Jeffe... OK no takers on measuring a bullet for me and I have to leave for the evening very shortly... So I took matters into my own hands and dummied up a Woodleigh 570gr .510 bullets FMJ bullet using screen measurements (page 49 of Terminal Bullet Performance thread) and computing the difference between the two knowns that I have (pulled from the Woodleigh website) .510 bullet diameter and 1.336" bullet length. Here is basically what I came up with to my earlier questions: 1) Maximum diameter & that specific location on bullet. .510” @ 0.100” and @ 0.9647” from base 2) Distance from base to point where bullet drops below maximum diameter. .511” @ 0.9647” from base 3) Distance from the bullet base to the bottom edge of the crimp groove. 0.5194” 4) Distance from the bullet base to top edge of crimp groove. 0.5565” 5) Diameter of bullet just above the top edge of the crimp groove. 0.510” 6) Distance from base to point where nose Ogive begins. 1.1875” 7) Diameter of bullet where nose Ogive begins. 0.2538” 8) Length of exposed lead core for the Soft Nose. 9) Total length of engraved bullet. 0.9647” So here it is...based upon my very sketchy measurements... & assumption of exact 2.65” case length: 1) Woodleigh 570gr .510 FMJ = 0.350" parallel sided freebore 2) CEB 570gr .510 BBW#13 FN Solid = 0.150" parallel sided freebore for the loaded cartridge to chamber without bullet seating engaging throat angle. So there we are and unless someone can come up with better measurements than I’ve noted above…guess we’ll have to go with it. On the off chance that a 500 AccRel ST shooter needs to use a Woodleigh 570gr bullet, or a RN bullets with similar measurements, I would recommend using Michael458’s specification of 0.375" parallel sided Freebore; that has proven to be very accurate in his 50 B&M and 500 MDM cartridges. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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agree Jim... We start with .25" freebore and then Anders has ordered the throat reamer so we can increase it until we r satisfied... | |||
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But please Jim or RIP - explain to me - what does this mean? Will I not be able to use the 570 grs Woodleigh bullet with a .250" freebore??? | |||
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Ulrik, If my measurements are close to the engraving results and measurements dimensions - then to answer your question - yes it does appear that you would not be able to chamber the 570gr Woodleigh with the following conditions: 1) case mouth crimped against the upper edge of bullet's crimp groove. And, 2) prepped case length is 2.65" 3) 0.250" parallel sided freebore To accomodate these three exact conditions requires an absolute minimum of 0.350" parallel sided freebore in the chamber. To allow for any lengthing of the case and variances in bullet construction I recommend you have Manson construct the 500 AccRel ST finish reamer with a 0.375" parallel sided freebore specification. This length freebore will not adversely affect accuracy nor will it result ib brass band abraiding; this is the same parallel sided freebore that Michael458 uses in his 500 MDM... I guess easiest to say, bullet specific requirements are: 570gr .510 Woodleigh C&C FMJ/SN bullets = 0.375" parallel sided freebore 570gr .510 CEB BBW#13 FN Solid/HP NonCoc = 0.250" parallel sided freebore Sorry I didn't think about testing a dummied bullet within the chamber throat specifications sooner... Least we forget - my measurements were done on a computer screen of a photograph which required me to compute to difference in size using only two known variables, either do which could be slightly off. I still would like to have actual measurements from an actual bullet. Jim "Life's hard; it's harder if you're stupid" John Wayne | |||
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Ulrik and Jim, I am on the road in the Dakotas. Don't have any sample bullets nor calipers in my pocket right now, so cannot measure. Don't think anyone can guesstimate by measuring images on the 'puter screen. Consider the 535 grain Woodleigh FMJ. That surely must fit into the zero-free-bore throat of the 500 Jeffery. You cannot tell that by Jim's 'puter measurements. Need bullet in hand to tell anything for sure. Posting the pictures from "page 49" of the 535, 570, and 600 grain bullets would make that evident to eyeball. | |||
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    Length A: Look at the engraving on the nose of the 535-grain Woodleigh FMJ. That supposedly works in a zero-free-bore 500 Jeffery Length B: Look at the length of the nose engraving (linear run along the long axis of the bullet nose) on the 570-grainer. B - A = parallel-sided free bore length to accommodate the 570-grainer. Eyeballing the screen: 0.295" - 0.222" = 0.073" That is by computer screen mesurement. Less than 0.1" for sure. But that requires using the same long leade (~ 0.75-degree) as on the 500 Jeffery instead of the shorter 1.5-degree leade on the 500AccRel-ST. So some more figuring on the leades ... See below. It does look like both the 535-grainer and 600-grain Woodleigh FMJ bullets were designed with the same nose ogive, to fit through the zero-free-bore, long-leade-only throat, that starts .511" wide and tapers down to bore. Presumably the length of nose engraving shows us over what distance the bullet nose tapers, from .510" to .500" diameter. Do we know for sure the Woodleigh bullets are .510" diameter instead of .509"? I do not have any to measure. | |||
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Still assuming .510" bullet diameter for the Woodleighs. Using the throat calculations Jim listed: 500 Jeffery (leade only): 0.4098" Proposed Short-Throat 500 AccRel (free bore plus leade): 0.2500" + .2397" = 0.4897" Difference in throats: 0.4897" - 0.4098" = 0.0799" That is greater than 0.0730". It will be a close fit by that calculation, but it will work. IMHO, between .250" and .500" length of parallel-sided freebore, would be usable, with .511" free-bore diameter. Split the difference to .375" of free bore or micro adjust as needed with the throat reamer to add onto the .250" free bore. Just glad to see Ulrik agreed to increase the free bore diameter to .511". Trimming the brass .010" shorter also increases the distance the bullet has to jump. Check my arithmetic. | |||
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