What does it mean to long throat a chamber? I have a m70 in 3006 sitting in front of me that is destined to be rebarrelled this winter to 338-06.

Seems the likeliest route is to get a load together next spring for 210 NPs but would like the option of the 250s if ever desired.

Barrel will simply be a duplication of the current factory contour but in .338 vs .308.

The throat dia. is extended farther out into the rifling allowing you to seat the bullet out farther. Usually you are limited by the magazine size unless perhaps you are using a single shot. roger

In theory with a long throat, you trade higher potential velocity for a potential loss in accuracy. The longer throat allow you to stuff more powder in the case and give the bullet a better run at the rifling. In exchange for this, you may not be able to seat the bullet close to the lands.

quote:

On average with a long throat, you trade higher potential velocity for a loss in accuracy.

Sorry, but I cannot agree with that statement, and have rifles to prove it. I have a 22" BDL 270 that allows me to shoot 60 grains of AA3100 in it. Cannelured bullets seated .005" off the lands have 1/4" behind the cannelure showing. The rifle clocks 130 Speer Grand Slams at 3150, and shoots to one hole at 100.

One other example is the 308 Norma Mag. That rifle is designed to have roughly 1/2" of freebore, and is one of the most accurate rounds in existence.

It would take a helluva long throat to get to the point you can't engage the lands with the projectile still in the mouth of the case. I think the only way that happens is to have a barrel with incredible throat erosion.

quote:

What does it mean to long throat a chamber?

What does it mean to long throat a chamber? I have found chambers that were 'throated', the reason is still known only to the person that did the throating.

5 Remington 03A3s were used to build 5 7mm Gibbs', the builder did all of the work including making the reamer, when finished and years one cam back with accuracy problems, he called me for ideals as to where to start, I told him to bring the rifle with fired cases, it did not make him happy but I took his fire formed cases and drilled the primer pocket/flash hole out and seated the longest bullet I have, I removed the bolt chambered the modified case and use a cleaning rod to push the bullet out? Out of the case before it hit the rifling, The throat on that chamber made the chamber so long it would have required a 7mm STW chamber to clean up, then nothing would fit, even if the barrel was removed and set back (2 threads).200 thousands the contour would not fit the stock, and, he dropped the reamer.

Long throat: the 300 Win Mag has a short neck, not a lot of bullet hold and heavy bullets take up room that could be used for 'MORE POWDER' so a few 300 Win Mag chambers have been throated, this does not mean the chamber will allow for a bullet running start, sometimes it means the bullet can be seated out to allow for MORE POWDER and a neck reamer can be use to cut the chamber for a case with a longer neck for added bullet hold, there are claims with a little reamer work on the 300 Win Mag it can keep up with the 300 Weatherby Mag.

Longer/heavier bullets take up room, the choices are limited, seat the bullet out with less powder or seat it deep and take up room for MORE POWDER, and then there are pressure issues. so throating is about keeping up with as many as four thought at once or same time, never let 'WHY' escape the thought process..

F. Guffey

quote:

Originally posted by Antelope Sniper:
On average with a long throat, you trade higher potential velocity for a loss in accuracy. The longer throat allow you to stuff more powder in the case and give the bullet a better run at the rifling. In exchange for this, you may not be able to seat the bullet close to the lands.

...if you want it to fit into the magazine. If not, seat the bullet where you want in relation to the rifling and single load...

It has also been discussed that seating bullets further from the lands with the same charge results in a loss of velocity.

quote:

...if you want it to fit into the magazine. If not, seat the bullet where you want in relation to the rifling and single load...

JSL said he plans to rebarrled his rifle to a 338.06 and shoot 210gr Nolser partitions. This sounds like a hunting rig, not a bench gun. Why would someone builing a good workhorse woods gun spend money on a new barrel to load longer then magazine length? So it's only reasonable to assume he will limit his reloads to magazine length.

For equal charge loads, you are correct. The longer throat will generally produce a lower velocity. A longer thoat will allow you to load to a higher chamber pressure. A good example of this is the old .223 ver 5.56 Nato debate. Yes, I have loaded for both, and on average, all else being equal, the 5.56 can be ran to higher velocities, but the .223 will shoot better.

What I do is throat mine to fit the magazine with a bullet I want to use. My gunsmith may average if I'm shooting two bullet the OAL.

I figure if I'm rebarreling might as well get it done for what I want to shoot. I also talk to my gunsmith and he's done enough chambering and if there be a problem he let me know.

I just had a 284 build he used a 6.5x28 chamber reamer and 7mm throating reamer and I long throated it to 3.100" vs factory @ 2.800" for 160gr bullets.

I build my stuff for accuracy first and velocity is what it is.

Well good luck.

quote:

Sorry, but I cannot agree with that statement, and have rifles to prove it.

I cannot agree with that statement and have rifles that prove it and disprove it. A small sample does not make the rule however as a rule the less guidance given a bullet the less accurate it will be.

tom raises an interesting point; for most of us I suspect a 210 gr bullet is adequate. Yet, if well built such a rifle could be used in the mountains including where bears may roam. a hunter could easily switch to 250s for the return trip. how would this impact the throating (if at all) of the rifle as set up?

When throating for multiple bullets, the question you must ask yourself is, do they have the same ogive/nose shape? If the nose shape is the same, the two bullets, when loaded to the same OAL will engage the rifling at the same time. If memory serves, the 210 and 250gr Nosler Partitions have about the same nose shape, so this shouldn't be a big issue.

On the other hand, in .227 the 150gr partition is a spitzer, and the 160gr partition is a semi-spitzer. At the same OAL, these bullet would have significantly different engagement of the rifling.

thanks, antelope. problem solved. use 210 and 250 nps and go forth. exactly what would be said to the guy installing the new barrel to properly communicate this message?

The single best way to do this is hand him a dummy round with your OAL and bullet of choice and tell him: "This is what I plan to shoot, please throat it to this."

Realistically, you have your action, your next two steps (if you haven't done so already) are to pick your smith, and pick your barrel. I typically recommend doing it in this order because some smiths may have a preference for, or a special deal with certain barrel makers or another. They may also be more current with any issues with a given barrel maker such as back log. Ultimatly, work with your smith the way he likes to be worked with. Most will like the dummy cartridge, others may have differnet methods they like.

There are pros and cons to throating a rifle shorter than standard chambers in order to load to the lands.

A pro would be that loading close to the lands may give you better accuracy. You can always seat deeper away from the lands but if you don't throat the barrel so that you can get close to the lands and still fit the magazine, then you will have no choice.

A con would be that the rifle will develop higher pressures with load book data. For example I have a 338RUM that I had the barrel chambered where I could load to the lands and still fit the magazine which is 3.685". I can not load to book max or I will lose the primer pockets. The book max is 98 gr RL25 with the 225 gr bullets but I can only load to 94 grs.

A con would be that you could not use factory ammo in that chamber and be sure of not developing pressure. For instance you would not want to short throat a Weatherby caliber and buy factory Weatherby ammo to shoot!

A con would be resale value on the rifle. Not being able to shoot factory ammo would decrease the value to all but other reloaders.

IMO best to tell the gunsmith to rechamber to factory SAAMI specs. Chances are almost 100% that you will be able to get a great hunting load, would be able to load to book data, would be able to use factory ammo and wouldn't have to worry about someone else or your kids putting factory ammo in it.

JMHO

I don't think he will find very much factory ammo for a 338.06.

quote:

Originally posted by Antelope Sniper:
I don't think he will find very much factory ammo for a 338.06.

You're right there. At least for right now. Guess I was thinking more generically for all rebarrels. My bad.

quote:

Originally posted by SR4759:

quote:

Sorry, but I cannot agree with that statement, and have rifles to prove it.

I cannot agree with that statement and have rifles that prove it and disprove it. A small sample does not make the rule however as a rule the less guidance given a bullet the less accurate it will be.

Rubbish, the Shultz and Larsen rifles for the 7x61, 308NM and 358NM were all throated with free bore (as were all the Weatherbys) and these rifles produced outstanding accuracy and high velocity to boot. Lyman and Sierra who seem to give unbiased data and comments in their reloading manuals both said the 7x61 cartridge in the S&H rifles gave superb accuracy with extremely high velocity for economical powder charges compared with many of the other magnums around.

My own experience with several 7x61 rifles proved this to be fact.

My old 404 Mauser has nearly 7mm of free bore with factory cartridges giving very good accuracy and also shooting lighter jacketed bullets at shorter OAL and cast bullets with the same degree of accuracy.

I've never got carried away with concerns over long throating (free bore).

The SAAMI spec on the 338-06 A-Square is 3.440. Not sure if Wby or Norma still making ammo for it be interesting to see a spec on that reamer.

quote:

Originally posted by woods:
IMO best to tell the gunsmith to rechamber to factory SAAMI specs. Chances are almost 100% that you will be able to get a great hunting load, would be able to load to book data, would be able to use factory ammo and wouldn't have to worry about someone else or your kids putting factory ammo in it.

Completely agree.

quote:

Originally posted by tom holland:
What I do is throat mine to fit the magazine with a bullet I want to use. My gunsmith may average if I'm shooting two bullet the OAL.

I figure if I'm rebarreling might as well get it done for what I want to shoot. I also talk to my gunsmith and he's done enough chambering and if there be a problem he let me know.

I just had a 284 build he used a 6.5x28 chamber reamer and 7mm throating reamer and I long throated it to 3.100" vs factory @ 2.800" for 160gr bullets.

I build my stuff for accuracy first and velocity is what it is.

Well good luck.

quote:

My own experience with several 7x61 rifles proved this to be fact.

My old 404 Mauser has nearly 7mm of free bore with factory cartridges giving very good accuracy and also shooting lighter jacketed bullets at shorter OAL and cast bullets with the same degree of accuracy.

Accuracty is relative. What do you consider good accuracy?

I'm not saying you cannot get good hunting accuracy from a long throated rifle. I'm saying that if you are building a new custom rifle, and intentionaly throat it with excessive free bore, you are giving up options that will effect you over all accuracy potential.

In the end, every rifle is as individual and flipitant as a woman, but at least we can choose how to build our own custom rifle.

I'm kinda in agreement with Woods' post above. I'm just beginning to learn something about throat of a chamber. I used to think the short throat where the bullet didn't have to travel far, was always best. I've got more than one rifle that seem to confirm that notion, especially my 338. I even carried this notion into the 458 project just delivered. I had the chamber cut with no throat, then cut the throat to basically 45-70 specs, which is much shorter than SAAMI 458WM. It will not chamber factory ammo, which is intentional, and a good thing. The results from my initial tests is that I didn't go wrong, since I'm handloading 350 - 400 gr bullets, which will allow normal seating depth, and have very short travel to engage the rifling. The accuracy is very, very good, so I'm not dissappinted, and the short throat theory vendicated.

However, I have several rifles with CIP spec chambers, with the long throats, namely 9.3x62, 9.3x57, 6.5x55, 7x57, 7x64. One would think that if the short throat theory is correct, then CIP chambers wouldn't shoot well, which is certainly not the case. And the bullets don't have to be seated out there either.

My CZ in 7x57 shoots well with bullets seated normal, and less as well if I seat the bullets out. The throat is so long that seating out enough to touch the lands would be difficult. With 175gr bullets, I gave up trying, after running out of adj on the seating stem, and backing off on the die several turns. I didn't even try with lighter bullets.

I shot my CZ in 6.5x55 just yesterday, with some Lapua 155gr Megas, seated both long and normal, same otherwise. In this rifle, the long seated bullets showed better accuracy, all else the same. Funny thing about this rifle is that with four different factory loads, and two handloads, the point of impact is so close to the same that I could actually hunt and mix the ammo, and have full expectation of success. The test was all at 100 yds, the factroy ammo was all 140 gr. in Federal, Winchester, PMC, and Remington, and the handloads were using 140 gr Sierra BT, and the 155 gr Lapua Megas. I've never had that happen with another rifle. I didn't expect that to happen. I was just shooting different loads for groups, and the result was if the groups were all overlaid, the collective group size I estimate at about 3.5 inches. And that's including the tests with the Lapuas, three different charges in one gr increments, short and long seated each (18 shots + 15 = 33 shots total. The best 3 shot groups were less than one inch. All that is counting the first shot from a cold barrel, and all additional shots from a warm barrel, since I waited between groups only long enough to keep the barrel warm - not hot.

My 7x64 also shoots well, and it seems to have the longest throat of them all.

One thing I noticed about the 7x57 is that a couple of grains of powder over book max actually reduced the group size, and showed no ill signs of pressure. Actually, I discovered it in the 7x57 unintentionally, when I mistakenly loaded the max load for a 140gr bullet, but used a 160gr bullet instead. Darn thing shot the best group yet, and I didn't figure out my mistake until I went to log the load into my notes, and saw that the charge was higher than previous loads, and I figured out what I did by looking at the book again. Oops, it could have been worse.

Of course the 458 is a different story. My loads for it are very conservative, and accuracy is outstanding. So far, I've seen no need to rush into trying to find max loads for it.

With the 9.3x57, I haven't been able to tell any difference in accuracy, whether bullets are seated long or short (normal). That rifle is accurate either way.

So, I'm not sure what to make of this long throat vs short throat business. One thing I think, but I'm not sure of, is that the CIP throats are tapered to the front, gradually getting tighter as it nears the full contact with the lands. In other words, I'm not sure that CIP throats are long freebore, but technicaly something different. Whereas, the SAAMI throats such as on my 338WM, and others, and in particular the custom 458 short throat, I'm thinking have a short straight throat and the engagment of the rifling is sudden, with no gradual transition.

Maybe someone could clear that up, and say how it really is.

Nevertheless, dispite all the above, unlessI had a real good reason to the contrary, I would have a custom barrel for a hunting rifle cut with a SAAMI throat. I usually have a particular bullet in mind that I want to try first, but generally the rifle shoots some bullet that I didn't plan on better than the one I expected to use.

So, throating for a particular bullet is not such a good idea on a hunting rifle, IMO, unless you are willing to correct a mistake by sending it back for more work after testing. I always want to try several bullets, maybe in a narrow weight range, to see which works best.

An example of exception is like when I ordered the 458 barrel, and specified the non SAAMI short throat, just because I wanted to, and I was willing to mess with it, and experiment. I sent eight dummy rounds to the gunsmith, (two each of four different bullets seated to the crimp grove) and asked him to cut the throat so the bullet with the longest full caliber ogive would chamber. The bullets in that situation were all 45-70 type bullets with a very short full diameter ogive and varying only a few thousandths in throat length needed. It worked out in that case, but it's tricky. So far, after testing, it appears that I made a good decision for what I wanted, but I haven't yet tried the Swift 400 gr bullets.

My 338 WM worked out real well, just by chance, and I'm pretty sure it's SAAMI spec, but I don't know for sure. When bullets that I prefer, such as 225gr Hornady Interbonds, or Nosler 225gr Accubonds, are seated just right, they fit into the magazine perfectly, and when chambered they are off the lands ever so slightly. It couldn't have been better if I planned it that way, but of course the Interbonds and Accubonds weren't even available when I had the rifle built.

KB

Long throating or freebore can actually help accuracy w/ some bullets. It's pretty well taken that barnes bullets like to be loaded off the lands, quite a bit in some rifles. I found this to be true w/ my 338x74K. Being a SS, loading long is no issue. I tried some TTSX in the rifle last month & the test loads were shooting under 1/2moa. The rifle normally has to work pretty hard to do that w/ std bullets in the chambers longish throat.

free bore/forcing cone, drop a bullet into the bore, it stops at the forcing cone/rifling, purchase a book on chamber drawings, Roy Dunlap on gunsmithing is an older book but a good start.

I want my bullet to have a running start.



F. Guffey

quote:

Originally posted by Antelope Sniper:

quote:

My own experience with several 7x61 rifles proved this to be fact.

My old 404 Mauser has nearly 7mm of free bore with factory cartridges giving very good accuracy and also shooting lighter jacketed bullets at shorter OAL and cast bullets with the same degree of accuracy.

Accuracty is relative. What do you consider good accuracy?

I'm not saying you cannot get good hunting accuracy from a long throated rifle. I'm saying that if you are building a new custom rifle, and intentionaly throat it with excessive free bore, you are giving up options that will effect you over all accuracy potential.

In the end, every rifle is as individual and flipitant as a woman, but at least we can choose how to build our own custom rifle.

Antelope Sniper I don't think anyone here is promoting "excessive free bore" and in the case of my 404 7mm freebore maybe excessive, i bought the rifle in this condition, may have been chambered this way for monolithics which do need a decent jump through the throat to keep pressures reasonable.

The original question was in relation to re-barrelling to a 338-06 which is a hunting round so we are not talking of trying for .25" groups. Accuracy in the Shultz and Larsen and Weatherby rifles is such that you can reach out to 300m plus ranges when on the open plains or in my case, the long river flats and open mountain ranges. Never had difficulty in placing my shots on target with the S&H rifle.

I have shot a lot of rifles on target and game over the years and have never concerned myself with freebore. Bullet, powder and primer selection in a given rifle is of greatest importance provided bedding is correct.

Does anyone know how to calculate the volume that is increased by adding to the throat?

IOW if you have .250" farther to the lands from the bolt face in a 300 win mag, how much more volume (percentage wise) compared to a 300 win mag that does not have that long a throat?

The case capacity of the 300 win mag is ~87 gr of H20 but that doe not include the volume from the case mouth to the lands.

Would it be correct to assume that you needed to apply that percentage of increase in powder to keep the pressure the same?

I know some of you guys are smarter than me, well at least I think so.

4.36 grains of h2o or .305 cc. roger

There ya go, thanks bartsche.

So does that mean that if you load both to the same distance from the lands (say .020" off), that you could load approx 4 grs more of powder in the rifle with the longer throat and get the same pressure?

Does it also mean that if your throat is receding that you have to load increasingly more powder to get the same pressures you had before?

Before I get flamed, I am not advocating loading 4 grs more, just postulating the question.

quote:

Originally posted by eagle27:

quote:

Originally posted by SR4759:

quote:

Sorry, but I cannot agree with that statement, and have rifles to prove it.

I cannot agree with that statement and have rifles that prove it and disprove it. A small sample does not make the rule however as a rule the less guidance given a bullet the less accurate it will be.

Rubbish, the Shultz and Larsen rifles for the 7x61, 308NM and 358NM were all throated with free bore (as were all the Weatherbys) and these rifles produced outstanding accuracy and high velocity to boot. Lyman and Sierra who seem to give unbiased data and comments in their reloading manuals both said the 7x61 cartridge in the S&H rifles gave superb accuracy with extremely high velocity for economical powder charges compared with many of the other magnums around.

My own experience with several 7x61 rifles proved this to be fact.

My old 404 Mauser has nearly 7mm of free bore with factory cartridges giving very good accuracy and also shooting lighter jacketed bullets at shorter OAL and cast bullets with the same degree of accuracy.

I've never got carried away with concerns over long throating (free bore).

Rubbish eagle,
You are saying the laws of physics do not apply to your example. They give outstanding accuracy as compared to what? Maybe you never got carried away because you have little experience with a wide range of rifles and cartridges.

quote:

Originally posted by woods:
There ya go, thanks bartsche.

So does that mean that if you load both to the same distance from the lands (say .020" off), that you could load approx 4 grs more of powder in the rifle with the longer throat and get the same pressure?

Does it also mean that if your throat is receding that you have to load increasingly more powder to get the same pressures you had before?

Before I get flamed, I am not advocating loading 4 grs more, just postulating the question.

Those are darn good questions. I would like to know the answers too. There is no need for me to speculate about that, because the chances of being wrong is too great.

I was noticing however, that a particular load listed for my 6.5x55 is compressed with the 155 gr Lapua Mega seated to the second grove, but it's not compressed seated to the first grove. I too am wondering what that does to pressure. Since the load in question is listed as max, with no indication in my rifle of too much pressure, it's possible that I could get an unscientific answer by just gradually increasing the charge in the load seated out, until it too is compressed, and see if signs of pressure show up. I'm estimating a 2 or 3 gr increase, about 1/2 gr at a time.

KB

quote:

The original question was in relation to re-barrelling to a 338-06 which is a hunting round so we are not talking of trying for .25" groups.

Are you sure?
JSL's been asking about this build in several forums. He's been asking about blue printing actions, and rifle cut barrels such as Kriger. You don't print the actions and screw on a Krieger unless you are looking to build a real tack driver. Besides, I like it when my hunting rifles shoot 1/4 moa groups....but then again, I don't limit myself to 300 yards either.

As for Weatherby rifles having long throats, Roy used every velocity enhancing trick in the book. OF COURSE HE WOULD LONG THROAT THEM. Stout actions, new rounds run at high pressures, long barrels (notice how he always used 26: barrels?), Norma powders, and of course a long throat. That doesn't mean weatherby wont' shoot, it just means that for the increased velocity potention, you are giving up some options that can effect accuracy potential.

Now I'm going to ask you to think into the future. After our friend has build his new rifle, what the next thing he's going to do. Well, there isn't factory ammo for the 338.06, so he will be back in this forum asking for load suggestions. I guarentee somewhere on the threat OAL will be discussed, and the standard advice is "start (enter very small number here) off the lands and move in. Well, if he long throated it, and can't get anywhere close to the lands without making it a single shot, I suspect he would be very disappointed.
Then the next post would be in "Gunsmithing" with a question about "bringing it in a thread", and tighting the throat, and, oh yea, recutting the pesky extractor grove, because after all, it is a Model 70 action.

quote:

Does it also mean that if your throat is receding that you have to load increasingly more powder to get the same pressures you had before?

Yes. Some distance shooters will do this. As the throat erodes, they will increase their powder charge.

I can only speak for what I do. I don't "Long Throat" as some call it to gain case capacity.

As to "short throat in a wby" I've had acouple Wby build without the Wby freebore and I don't look at buying factory ammo or resale.

Custom throating on the Wby been around a long time. In Speer manual #14 if you look at the loading data for the 300WBy they give a warning about custom rifle and Lymann #45 published 1970 gave a warning on the start loads.

This is from the Nolser forum and this is how Woods told a poster how to throat and AS agreed
"Along with your action send an unprimed load seated to the depth you want and tell him to set the lands there. If your magazine is the controlling factor then get a box of 200 gr Accubonds (long ogive and plastic tip) or 210 gr Partitions (excellent bullet but not ultimate accuracy) and seat one .025" shorter than your magazine length, that will allow you to seat the loads .025" off the lands and have .050" clearance in the magazine and give you a little room for throat recession."

quote:

Originally posted by tom holland:

This is from the Nolser forum and this is how Woods told a poster how to throat and AS agreed
"Along with your action send an unprimed load seated to the depth you want and tell him to set the lands there. If your magazine is the controlling factor then get a box of 200 gr Accubonds (long ogive and plastic tip) or 210 gr Partitions (excellent bullet but not ultimate accuracy) and seat one .025" shorter than your magazine length, that will allow you to seat the loads .025" off the lands and have .050" clearance in the magazine and give you a little room for throat recession."

Excellent advise if you plan to throat to get close to the lands. That is the way I did my custom chambers in 280AI, 6.5 rem mag and 338RUM. After seeing how the 338RUM had primer pocket problems with what would be under book max at 95 to 98 gr RL25, with the latest rebarrel I did to a 375 Ruger I instructed the gunsmith to "Ream to factory specs". That is normal freebore and no tight neck.

Woods, I have a question on the 338RUM that you post pictures of your groups and gave loading data on Nolser forum. Did you ever trying seating the Barnes bullet deep than .025 and did you spec the tight chamber?

Hey tom, IIRC I sent a dummy cartridge (225 gr Accubond) to the smith with a OAL of 3.620" since I have a mag length of 3.685". Thought that would allow me to seat the Accubond .020" off and allow .050" or so of throat recession before the barrel is gone and still fit the mag. I did spec the neck at .366" which would allow me to do a complete turn of the brass even if I got a batch with thin necks.

I do load the 225 gr TTSX at .050" off and it has a shorter OAL of 3.578".

However, if I had it to do over again I probably would just tell him "factory reamer". Not that I am displeased with the tight necked short throated chamber I have, just that I do think I would be just as satisfied with a larger normal chamber. The most accurate rifle I have has a large chamber and .085" clearance around the neck with an unturned brass load. I recently shot a 300 RUM belonging to a friend that had .011" clearance around the neck and .160" jump to the lands and can still shoot 1/2" groups at 200 yards.

Why bother?

.085 difference in neck Clarence is the same difference between a 25/06 neck and the neck of a 338/06 + or - very few.



F. Guffey

Yep, good catch, missed a zero

.0085"

quote:

Does it also mean that if your throat is receding that you have to load increasingly more powder to get the same pressures you had before?

I can't discuss pressure but I can discuss velocity. I had a VS 22-250 that I used on Pdogs. I had set the jump to the lands by the very sciencetific method of blacking a bullet and adjusting until I no longer got marks from the lands. Each spring I would reset the COL and, using my Chrony, I would add powder until I achieved my original velocity. FWIW, the results would shoot almost to the same POI. When I finally sent the rifle off to be rebarreled, my load was well out of the book, and the bullet was well out of the case.

Despite the examples of one that contradict him, I agree overall with what Antelope Sniper is saying. When RW first brought his rifles out, the writers were quick to point out that the velocity he was selling was achieved only by long throating his rifles. And that accuracy was not what it would be if a more conventional throating was used. With, of course, load adjustments.
I've never owned a Weatherby so I really don't have a dog in that fight.
I agree with Wood that a conventional chamber (factory) is the way to go. Too exotic and the re-sell value of the rifle goes to zero.

quote:

Originally posted by woods:
Yep, good catch, missed a zero

I've tried to tell you about using those "Thingys". Actually being off only 1-Zero is pretty good for them.