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Cooper Rifle - Long Throat?

 
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  #1  
Old 10-07-2013, 06:03 PM
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Join Date: Sep 2012
Location: Nova Scotia, Canada
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Cooper Rifle - Long Throat?

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%."

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  #2  
Old 10-07-2013, 07:10 PM
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Location: Greencastle, PA
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Re: Cooper Rifle - Long Throat?

My 6.5 Creedmoor is the same way. Even with 140 amax I have to jump them .040 to fit the mag. The 130 berger load is super accurate and is jumping .120 so it doesn't seem to hurt the accuracy.
My mag is only 2.82
You may have to stick with conventional type bullets if you can't get the VLD type to shoot well, but I have been able to find a seating depth with most bullets to get them to shoot very well even with a huge jump in some cases.

Last edited by 8andbait; 10-07-2013 at 08:02 PM.
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  #3  
Old 10-07-2013, 07:22 PM
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Re: Cooper Rifle - Long Throat?

This is one of the problems with factory rifles. Often the throats are reamed too long to seat bullets close to the lands and still fit in the magazine. ESPECIALLY in short actions. They do this in part, I think to avoid any liability issues. The only short action factory rifle I would consider buying would be a 6.5x47, or 22 cal something or something with a case OAL of 1.9" or less depending on make of rifle. The factories don't make rifles for guys who load to the lands, if they load at all. Cooper does make rifles knowing that many of their customer will develop loads for them.

In your case, If you load to fit the magazine and have a .060 jump you'll probably just fine and I doubt you will loose much accuracy life. Just a bit of a pain not to be able to have more seating depth options. When you start to get some accuracy degradation you can always set it back a little and readjust the throat but you will probably loose a good inch of barrel... or just do a complete rebarrel the way you want it.
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Old 10-09-2013, 02:02 PM
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Re: Cooper Rifle - Long Throat?

Thanks for the reply guy's. I guess I'll have to try a few loads and see how it goes.
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  #5  
Old 10-09-2013, 04:39 PM
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Re: Cooper Rifle - Long Throat?

I have a M52 in 280AI that has a similar issue - I need to be about 40 thou off the lands to get 160NABs in the box. I am much farther away with 168 VLDs. This was slightly annoying to me at first - BUT - the rifle shoots really good with some jump. Really good. Every bit as good as a custom I have from a reputable builder (and LRH site sponsor). I'm willing to overlook the perceived loss of loading flexibility because I don't need it to make it shoot good...

I also have a M54 in 22-250 that is the exact opposite. It likes 50 gr pills, and I think I could seat them 10 thou into the NECK and still fit 'em in the mag. I shoot them 5 thou off the lands and that rifle shoots really well too - I sometimes wonder if it would shoot as good with more jump but have no reason to try.

I think Cooper uses the same bottom metal for each individual action (M54, M54, M56) and as such you are constrained in the longer offerings for each action. (Hope this reads clear - same bottom metal for cartridges in each action, not same for all 3 actions).

On a purely editorial note, with both of these rifles, I DEMANDED a mag fed rifle. Looking back I can literally only remember a few times where I jacked a second round in, and I think in those cases I didn't shoot again. All my range work is single shot. In reality, a single-shot model would probably work fine for me and would take away any mag box issues as well.... I just can't bring myself to it.

Last edited by varmintH8R; 10-09-2013 at 04:44 PM. Reason: Clarify statement on bottom metal
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  #6  
Old 10-09-2013, 06:16 PM
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Join Date: Apr 2010
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Re: Cooper Rifle - Long Throat?

I also have the Cooper 7-08 but walnut/blued. I am working up a load with 140 VLD's and find I am 0.090 off the lands if I want the bearing surface of the VLD to be in full contact with the neck brass. I could set the bullet out to 0.060 off the lands and barely fit the magazine (2.83") but would have less bearing surface grasped by the neck. Heavier bullets (ie 168 VLD's/162 AMAX etc) you can get close to the lands but then cannot fit in the magazine.
The 140's shoot fine (.5-.75 MOA) with my rifle using Varget at 0.090 off, so I think my load development for this rifle is almost done.
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  #7  
Old 10-10-2013, 11:47 AM
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Re: Cooper Rifle - Long Throat?

Every gun I have is single shot or I convert to single shot.
When I feel like I can't hit what I'm shooting at, I don't shoot. When I miss, I don't shoot again.
It lives another day
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