Cooper Rifle - Long Throat?

deertroy

deertroy

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I have a question about Cooper rifles. Has anyone noticed if they have a really long throat or is it just mine?

I got mine back from Cooper last week. It's an all stainless M54 7mm-08. In setting up some handloads I noticed that I can not get anywhere near the lands with any bullet and still have the ammo fit the magazine. Most bullets would need to be about 2.9" to reach the lands. The magazine will only accept about 2.85".
One down side to this is even if the rifle shoots good, barrel life is shortened substantial. Here's a partial C&P from Shilen's web site:

"Factory rifles are made with throats long enough to accept the largest bullet that is offered in factory ammunition for that chambering. So if the throat is long enough to accept a 200 grain bullet and you only want to use 150 grain bullets, then the throat is so deep you can't get the bullets close to the lands and keep them in the case. What this amounts to is the factory reamed out a couple of hundred thousandths (or more) of lands and grooves in the throat, which shortens the accurate life of the barrel by as much as 50%."
 
Thanks for the info leeelmer. Maybe some other Cooper owners will chime in.
I just checked the 100gr Sierra's and they're not that bad. Looks like there's hope after all. I guess I should probably find time and actually shoot this thing?
 
I have owned in excess of 20 center fire Coopers since 2008, all but 4 were single shot, the pix I have included shows on the left side a 257 Roberts with a Nosler 115gr seated to fit the mag of a Model 54, the next round is a 257 AI on a Cooper M-22 single shot, also loaded with a Nosler 115gr, quite a difference. The next cartridge is a Federal factory 6.5 X 55 140gr, next to it is the same cartridge with a Berger 140gr VLD seated to fit my M-22 Cooper, again a considerable difference, both these M-22's shoot .250 moa. My Model 54 257 Roberts shot consistent .375 moa with this load despite being some distance off the lands, as far as long throats and short seating cutting barrel life by 50%, thats something I am not aware of.

IMG_1259_zpsf7e5375a.jpg
 
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With my 280AI rifles, I could load almost to the lands, and still use the magazine. With my 7mmSTW rifles, I can't get closer than around .070" off of the lands. As to the accuracy life of the barrel being shortened by 50%, the author could be referring to the fact that as throat erosion occurs, you need to lengthen the COL to keep the bullets seated to the lands, and a long throat can limit this with some bullets. If you need to load to the lands, or to just off the lands to achieve acceptable accuracy, with your rifle and load, a long throat could be an issue. However, if your rifle shoots well with the bullets seated well off the lands, this won't be an issue, and you won't be sacrificing any barrel life. As to factory rifles having long throats, this is common with most brands, not just Cooper, especially since the latest craze in long, high B.C. bullets became so common. As a matter of fact, I am having a custom precision rifle being built, and I specified the bullet that I wanted the chamber throated for, and I am also having the magazine box extended, to ensure that I will be able to load to the lands, and still use the magazine.
 
stubblejumper said:
With my 280AI rifles, I could load almost to the lands, and still use the magazine. With my 7mmSTW rifles, I can't get closer than around .070" off of the lands. As to the accuracy life of the barrel being shortened by 50%, the author could be referring to the fact that as throat erosion occurs, you need to lengthen the COL to keep the bullets seated to the lands, and a long throat can limit this with some bullets. If you need to load to the lands, or to just off the lands to achieve acceptable accuracy, with your rifle and load, a long throat could be an issue. However, if your rifle shoots well with the bullets seated well off the lands, this won't be an issue, and you won't be sacrificing any barrel life. As to factory rifles having long throats, this is common with most brands, not just Cooper, especially since the latest craze in long, high B.C. bullets became so common. As a matter of fact, I am having a custom precision rifle being built, and I specified the bullet that I wanted the chamber throated for, and I am also having the magazine box extended, to ensure that I will be able to load to the lands, and still use the magazine.
Click to expand...

Thanks for the reply. I was going to PM you and ask your opinion. Shilen was referring to exactly what you said in bold above. If I was going the custom route I would specify the throat, dependent upon what bullet I was wanting yo use, as you have done as well. I guess I'll shoot it and see how it goes. Thanks for the reply.
 
I have a Cooper in 30-06 that doesn't seem excessive although it's shooting 180's.. I do have a Sako 85 in 7-08 that seems a long way off that lands when holding max coal using 140 grain bullets. Did manage to tune them to 20 thou off the lands and they just fit in the mag.
 
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