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How conservative are published loads?
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Picture of Gatehouse
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I've rarely exceeded maximum published loads (published in manuals such as Nosler, Barnes, Speer, Hodgons)And when exceeding them I've always been very conservative, like a grain over in a standard or regular magnum case.

However I've seen over max loads posted at various internet forums, in Rifle and Handloader, and various other places that usually have knowledgable info. (Don't worry- I'm not going to try out loads from unconfirmed sources- like some guy that just popped up on the internet)

Basically, I presume that the staff at "Handloader" have acess to Nosler manuals, so why are they exceeding the max load for a .270 with a 150gr Partition? (I just chose .270/nosler arbitrarily)

Usually when I'm working up a load, if I get to max, then I play with seating depth etc. But there is often LOTS of room left in the case, especially if the bullet doesn't need to be seated too deeply.

If I get good accuracy, with no pressure signs, I'm usually happy. What do you do? Do you strive to fill the cases up to 95% or do you not care?

 
Posts: 3082 | Location: Pemberton BC Canada | Registered: 08 March 2001Reply With Quote
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Picture of Bob338
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Those published loads are tested with pressure measuring equipment. The barrels or guns used are usually specified. There is significant effect from chamber and barrel dimension variances. Obviously the best way to judge any published load is to check pressures of that load in your gun. Absent pressure testing equipment, a chronograph is also quite useful. You can bet when you achieve the same velocity as the published load, your pressures are near maximum and probably the same as those printed with the published load.

When you get the usual pressure signs after firing a load, you can bet you have exceeded the same SAAMI pressures for that case. Conversely, you can exceed SAAMI maximums and show no pressure signs. It's always best to stay within the safe velocities and pressures published for that particular cartridge.

Much of the reason loads are thought to be conservative today compared to the past is that our pressure measuring equipment is significantly better today. Litigation does enter into it but all that does is make everyone a bit more cautious and safer.

Don't exceed maximum published loads without some form of testing equipment. With a chronograph, don't exceed maximum published velocites. Best to be safe than sorry and those extra 100fps won't make a bit of difference on game if you hit where you aim.

 
Posts: 1261 | Location: Placerville, CA, US of A | Registered: 07 January 2001Reply With Quote
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I normally don't like to use powders that don't fill or almost fill the case to the base of the bullet and I usually try for just "a little bit of compression"...seems to make more consistent loads for me. Depending on what you are loading for, if you have a lot of space left you might try going to a slower power that is recommended.
 
Posts: 4360 | Location: Sunny Southern California | Registered: 22 May 2002Reply With Quote
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Bob's answer is so dead-on... almost hate to try to add to it, but here goes.

As nearly as I can figure this thing out, the effect of going over the published limit is not sudden, catastrophic failure of the gun. It is greatly decreased firearm life.

There is a general rule of thumb in this type of situation that as the applied stress goes up linearly, life decreases exponentially.

Pressure signs generally do not show up until you are far past the SAAMI specs.

 
Posts: 2281 | Location: Layton, UT USA | Registered: 09 February 2001Reply With Quote
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Hey Gatehouse, Sometimes you can go over published Loads and sometimes you can't. I do agree that is why we all have to "develop" a Load specifically for our rifle, case, primer, powder and bullet combination.

For example, in the Speer #13 Manual for a 150gr 308Win Load, if I just picked the top Load shown for RL-15, it would have been too high for mine. My Lot of RL-15 is simply faster than their Lot. But, using the WW748, (in my current 308Win) it is possible to exceed their listed Load with "some bullets" but not with others.

I completely agree with you that using someone elses Load information from ANYWHERE other than one of the actual Component Manufactures Manuals is just not something I'd do. And as just said, even using the actual Component Manufacturers Manuals, you still need to "develop from below".


No argument with Bob338's method at all, it works well for him and lots of folks. I prefer to use actual Expansion measurements from both the Casehead and Pressure Ring to know when I've reached a SAFE MAX Load level.

About the only people I've seen write about it during the past 45 years are Bob Hagel, Ken Waters and a brief mention of Casehead Expansion in each Speer Manual.

I like Case Expansion measurements because you are getting information "directly from" the weakest link - the actual Case. You do need a set of Micrometers with 0.0001" capability (0.001" capable Calipers are just not accurate enough), but this very old method still works great today.

------------------
Good hunting and clean 1-shot kills, Hot Core

 
Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001Reply With Quote
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No first-hand experience with blow-ups, but a LOT of reading. I'm sure Bob338 is exactly right. If you want to read several pages of explanation as to why he's right, see Art Alphin's A-square reloading manual, available from Sinclair. It's a very good manual for big-bore reloaders, and pretty good for others, also.
 
Posts: 2272 | Location: PDR of Massachusetts | Registered: 23 January 2001Reply With Quote
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I think it would be productive for all reloaders to witness a blow-up from "up-close".....kind of like taking your teenage kid to witness what a car accident looks like on the express way....bottom line: slow down and do observe the speed limits. The results can be catastrophic and....for what?
 
Posts: 89 | Location: New Canaan,Ct., U.S. | Registered: 18 September 2000Reply With Quote
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I think you should follow the old race car adage. "If you're too slow, get a faster car." If you aren't happy with book loads in any given caliber, get a bigger gun. NO increase in velocity is worth the possible injuries caused by a blown gun. Seen it happen, don't want to see it again. I shoot 11 different rifles, load for all of them, and never load to book maximum. Max loads are usually not the most accurate anyway.
Just my opinion

------------------
Jay
"For God and Country"

 
Posts: 282 | Location: Mid-Hudson Valley, NY | Registered: 26 July 2001Reply With Quote
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So am I to understand that the loading books don't allow a buffer zone for litagation minded folks???? " Bet me.....

Many of my loads are a grain or two over book max and have been for years. My old books show the same dispersion...

It is your call and depends on your actual reloading knowledge and experience but in my opinnion most loads can be exceeded and most of the folks in the know do it...Rifles vary to such a great degree in which loads they will take that one has to work up what the individual rifle will take.

I only speak for myself and not for anyone else, as I have been reloading for near 50 years or more and I know what I'm doing, how to mike cases etc. and that does make a difference........When one is a reloader he is on his own and his mistakes are his alone.

Even the loading books vary by several grains....Start low and work up when you get near max the velocity increases will normally drop to 15 to 30 FPS per grain of added powder..so cut back a grain at that and your brass will last longer and that increase is not worth the trouble.. You may or may not be over book max at this point....

Case life is a good indicator of your max load..

I recommend new reloaders stay under max until they are 99% proficient at the bench..The learning period is where the bad stuff happens, but not allways...I have never blown a gun but I have popped out a few primers and had one gas leak but that was a 243 and not a hot load..They have a habit of that when throat wear starts, but thats another subject....

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

 
Posts: 41859 | Location: Twin Falls, Idaho | Registered: 04 June 2000Reply With Quote
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Well, sometimes one has to wonder. In one loading manual the loads for the 7x57 Mauser with 175 gr. bullet dropped from 2500 FPS to 2300 FPS from the 4th to 5th editions. The only change was they used a Ruger Mod.77 in the 4th ed. and a Winchester Mod. 70 in the 5th ed. A change in rifles cause a 200 FPS drop, with a major reduction in powder charges. Something to think about.
Some cartridges are deliberately kept to lower prssure data because of the weak rifles they originally came in. Maybe these rounds should also be loaded as a Group 2, like that which is done for the 45-70.
Something to think about.
Paul B.
 
Posts: 2814 | Location: Tucson AZ USA | Registered: 11 May 2001Reply With Quote
<Slamfire>
posted
I've got an old Arisaka carbine that thinks the published loads in Lyman's manual are way too hot. By the same token it thinks I can safely exceed those in the Hornady manual. I always let the rifle decide what's hot and what's not.
 
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<stans>
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There is a great deal of variation from one barrel to another. I once worked up identical loads in .357 Magnum, not exceeding the published maximums. My Ruger GP-100 had no problems with extraction of fired cases, however, I had to bang on the ejector rod of my Dan Wesson 15-2 to get the cases out. There were pressure signs in the rounds fired from the DW, I attribute this to variations in the chambers and barrels.

Work up loads that are safe in your firearms and never give a friend a handfull of your ammo to try in their guns if your ammo is anywhere above a mid-range load. You probably shouldn't give anybody your handloads anyway, unless they are going to test them in a pressure barrel.

 
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Picture of John Y Cannuck
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I read somewhere that Bruce Hogdon said he reduces his "Max" loads by 10% before publishing.
I have used loads over max on numerous occassions without incident, but I don't anymore the gains are not worth the losses.
To case life, rifle life and my life not to mention pain in the shoulder for certain bigger bores. Accuracy usually suffers as well. Just aint worth it.

I will make one exception. The max loads listed in my Speer manual for my 6.5X55 Swede are pathetic, they don't even expand the case. I now use a max load published by Lyman that equals Norma factory stuff.

[This message has been edited by John Y Cannuck (edited 08-29-2001).]

 
Posts: 872 | Location: Lindsay Ontario Canada | Registered: 14 April 2001Reply With Quote
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Terry Wieland has an article on this in the current Gray's Sporting Journal--using a 6.5 Swede and a P17 Enfield he started loading them beyond max with a fast-burning powder.
He increased the charge one grain at a time and fired them with a string from behind a barrier.

IIRC one went from flattened primer, to pierced primer, to jammed bolt, to a complete blowup in successive one-grain increases.

 
Posts: 1246 | Location: Northern Virginia, USA | Registered: 02 June 2001Reply With Quote
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The concept of a "maximum" load cited by any one souce is an errant one.

Any manual uses one firearm, whether a conventional rifle, or a switch-barrel pressure gun, to work up its published loads. The maximum they list is the maximun they recommend in that PARTICULAR gun (with perhaps a safety margin). EACH rifle is a rule unto itself, and will likely give a different pressure and velocity with a given load than any other rifle. Variables such as chamber dimensions, bore size, rifling type, bore finish, etc., make it impossible to predict the exact "maximum" for any one gun.

Maximum also relates to what it is that you wish to achieve. Do you just want one firing from a case? If so, your "maximum" will be several thousand PSI above the "maximum" of someone who wants indefinate case life.

Do you want slick action operation and easy reloading? If so, then your "maximum" is less than if you don't care if you have to hammer the bolt open with each shot.

I'll swear, I've known shooters who claimed that Manual X was "better" than Manual "Y" because "X" listed two more grains of 4350 and 50 FPS more velocity as "maximum" compared to "Y".

I have a .270 which won't start to digest the time-honored charge of 60 grains of 4831 behind a 130 grain bullet for 3140 FPS without unreasonable pressure signs, but gives 3200 FPS with only 58.5 grains of powder. So why should I complain?

On the other hand, one of my .223's needs almost 8% more H335 than usually recommended to achieve normal pressure and velocity.

"Maxumum" is whatever works in YOUR INDIVIDUAL RIFLE.

 
Posts: 13235 | Location: Henly, TX, USA | Registered: 04 April 2001Reply With Quote
<Harald>
posted
Getting back to your original question, part of the answer is that they sometimes are well over standard SAAMI limits. All SAAMI cartridges tend to get tested using pressure barrels, but all of those wildcats and proprietary cartridges for which words like "there are no SAAMI established pressure limits for the .xxx Whosafudgit but the loads shown were safe in our test rifle" will sound familiar have possibly been tested using the same method that you and I use. Look at the loads for the .300 Weatherby in the Speer manuals going back two editions to the time before SAAMI included that cartridge and you will see what I mean. I recal a 5 grain reduction in one max charge between the old loads and the pressure barrel loads that appeared in the following edition of the manual. Generally, though I think that Ray is absolutely right, they endeavor to have a reasonable margin for liability's sake. The difficulty is that (as has been noted) all rifles are unique and some published load development over the years has been done in rifles with highly atypical barrels.
 
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