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Location: Montana
Joined: 06/08/2005
Posts: 85
7mm Mag not grouping

I loaded some rounds following the Hornady manual for my Rem. 700 CDL 7mm Mag and the bullets were shooting a 6 inch group at 120 yards and a 4-5 inch group at 50 yards. Not impresses to say the least. The rifle has shot 2 inch groups at 200 yards, so I ruled out the rifle and/or scope, or me. 

I used R-22 60 grains, and repacked Core-loks 175 grains which I bought from Midway USA. I'm thinking its the bullets but not for sure. I have had good success with Remington Core-loks, but these bullets don't look consistanly molded. And I'm not for sure that they even core-loks because  of the packing from midway usa. The casings were about .002 over-length, but I have now completed trimming to proper size. Any suggestions would be appreciated, if not I have about 95 "core-loks" bullets for sale.

thanks

 

 

Critter's picture
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Location: Western Colorado
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Posts: 3921
So what round were you

So what round were you shooting to get the 2" groups?  You might want to try either a different powder or lower the powder charge and see what happens.  Rifles and reloading are not an exact science and you need to play around to find what your rifle likes as far as reloads.  I have some that hate one type of powder or bullet and love others.  That is one of the fun things about reloading. 

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Location: Montana
Joined: 06/08/2005
Posts: 85
Remington Core-loks 150 grain

Remington Core-loks 150 grain and 175 grain factory loads. I think improper cleaned primer pockets were the issue. Or old primers. 

Critter's picture
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I doubt that either one of

I doubt that either one of those would cause the groups to open up.  I have been using primers that I bought in the early 90's and haven't noticed any problems with groups. 

Don Fischer's picture
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Location: Antelope, Ore
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Primer's, dirty pockets ect

Primer's, dirty pockets ect won't turn a 2" rifle into a 6" rifle. If you've had the rifle apart, check the action screws that theey are tight. Most guy's set them with a torque wrench, I just guess. Make sure the scope is not loose. Should't be a bedding problem as factory stuff shoot's well. Shouldn't be a powder problem either as the change is to drastic. Did you get the bad group's before trimming the cases? That could have been the problem. When you start janbing the necks into the lands it raises pressure. Could be that some cases were alright and some weren't in varying degrees. If one case is to long, trim them all to the same length.

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Location: Wa.
Joined: 03/31/2004
Posts: 1300
Welcome to reloading I would

Welcome to reloading Confused

I would start by tightening all of the screws on the rifle. On the action, tighten the forward screw first. Fire some factory loads with the same weight as you want to reload. If they group to your satifaction then the chances are it's not your firearm.

Start the loading process from the beginning. Tear down all of the loads you made. Full length resize all of the cases. Trim all of them to manual specs. When you seat the bullet. Be absolutely sure it is seated to the length the manual calls for.

If your absolutely sure on what powder you had used, save it. If you're not absolutely sure throw it away. Load enough rounds, at the minimum load in the manual your using, to check for grouping at 100 yds.

note: The primer manufacturer shouldn't make enough difference. Some manufacturers cases have a bit less or a bit more capacity, which can increase or decrease pressure. Especially, with heavy or maximum loads. Hence, start with minimum load. If you care to, you can roll the bullets on a flat surface to check for shape.

Go slow and meticulously. Once you get it to work. It's very gratifying.

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Location: Neveda
Joined: 07/22/2008
Posts: 179
this may sound trivial but

this may sound trivial but make sure you are starting with a clean bore: i will agree with the post above: he beat me to the same information.

you might want to find the torque specs and invest in a good inch pound torque wrench

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Powder Charge

Since you know the rifle shoots decent with one factory load we can pretty much eliminate the rifle as being a cause of such groups.

My suggestion would be to try various powder charges. I've found that a few grains either way, more or less powder, can do wonders for accuracy. Reloading is a process of elimination and finding what the rifle likes. Once I find a load that works I don't change anything and stick with it but that's just me and I hate expirmenting.

If, after trying various loads, you still aren't happy then try a different powder. It's why I don't buy powder in bulk until I'm sure that the powder will work for me. I don't have a lot of expirience reloading but this is part of the little bit I've learned since I started loading again.

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