group difference

a few questions, purchased a new Cabelas model 12 FV in 223, worked up a load, the 75 Amax's were shooting tight, then i install an aftermarket stock, did not like it, put old stock back on and the 75 amax's will not shoot tight, but the 69 SMK do, is the difference in the group more related to the stock reinstall, i did torque the screws as i did before, 50 in lbs on the front and 30in lbs on the rear.i'd like to get the 75 amax;s to work again, any ideas. and also when i got the gun after about 50 shots i measure the throat length with the 75 amax, and now after 350 shots the throat measures about .025 longer, is this normal wear, do aftermarket barrels show any longer wear

Chet

If the only thing that changed was removing and replacing the stock then the answer should be torque or how it was torqued but since you shot it with different bullets from a different maker you may need to clean the barrel. Doesn't always happen but i have seen different bullets or powder for that matter mess with accuracy of a known load for a number of shots or until barrel is cleaned at least some. Those two places are where i would start with the first being the stock.

Savage Action Screw Torque Tuning

This article originally appeared in the SAVAGE ACCURACY Blog

http://www.accurateshooter.com/techn...torque-tuning/

Here's a good read regarding stability :http://www.bergerbullets.com/twist-rate-calculator/

Plug in your numbers and get a stability rating. Anything over 1.5 is acceptable. You'll need to measure your bullet OAL. I just shot my last one so i can't supply the dimension for you.

And a bonus read: http://www.primalrights.com/articles...nding-pressure

IIRC, max torque on the plastic stock is 35 in lbs front and 20 rear. You may have over torqued it and damaged the bedding/pillars.

I've had mine apart multiple times and never had this issue. I think earl39 hit the mark on his reply.
Clean it well, then give it a few rounds to foul. I personally torque the screws at 30 inch pounds, front to rear, in 10lb increments.