Cold bore POI 243 95 gr vld

[Luke45]

So I got some great handloads worked up for my 243, 41.5 gr N160 with 95 vld at the lands. 3/8 Moa. What's completely blowing my mind is that with a dirty cold bore, first shot hits 1.5" high. The flowing 5 shot group is 3/8 Moa. Then I do a deep clean an shoot it the next day and first clean cold bore shot is 1.5" low followed by 3/8 Moa 5 shot group. Makes me afraid to take it hunting what do you think?

[Luke45]

Sorry had a typo, cold dirty bore first shot was 3.5" high

[CharlieNC]

How many rounds thru the barrel total, and on this cleaning cycle you are calling "dirty". You may need more shots before cleaning to equilibrium.

[Luke45]

Cold and Dirty was 25 rounds without cleaning.

[Luke45]

It's a new barrel. 100 rounds through it

[foxx]

Was the "clean" bore also oily? From my experience, any oil will throw off shots like that.

[Luke45]

Hey foxx, yes the clean bore shot probably had trace oil. I cleaned the rifle every 5 shots for the first twenty shots just for formalitys(its a shillen match barrel, so its been lapped and probably doesnt need to be broken in). and then cleaned all the copper out after about 75 rounds to see if a clean cold bore shot was even close just out of curiousity. It blows my mind that a fouled dry cold bore shot is consitantly 3 MOA high. i think im just going to keep shooting without cleaning copper out and see if the cold dry dirty shot gets any closer. if not, its going to have to turn into my long range Pdog gun

[CharlieNC]

Stop cleaning and just shoot it, and it should settle down. Be careful esp with 243 not to overheat the barrel.

[emtrescue6]

Stop cleaning and just shoot it, and it should settle down. Be careful esp with 243 not to overheat the barrel.

+1....shoot it till you see groups start to open up...then clean it and repeat. To many people "over-clean" their barrels...

[Luke45]

Ive now taken it to the range twice since then. 60 rounds with out cleaning, consistant 3/8 5 shot MOA. First shot is still at minimum 2 MOA high out of a dirty cold barrel. tried three different bullet wieghts all same story. MY recoil lug is not bedded. Could this have something to do with it? Maybe its shifting in the first shot? Id ont want to hunt big game with a gun thats going to have a cold shot 2 Moa away from the second shot, to complicated in the field

[Westcliffe01]

You have some sort of stock/bedding/action/action screw issue going on. As if your action is not seated properly, then setttles after the first shot.

You should 100% fully bed the action and recoil lug and install pillars to take the action screw stress out the stock material (wood or plastic). Make sure you get a decent thickness of a re-inforced beding material, not a skim coat. You should immediately note that tightening the action screws after has a "non springy" feel to it.

I forget if this is a plastic stock ? Plastic is just a terrible material for a stock. Elastic and slick. Bad combination. If they cast a bedding block into it, it would not be so bad.

[Luke45]

Thanks for the Input westcliffe, it is a choate varmint stock and has the full aluminum bedding block. Would you reccomend bedding over the top of the aluminum or just the recoil lug area? I have a feeling that you are correct, that there is some type of stress that is relieved after the first shot. Just trying to pinpoint the issue

[CharlieNC]

On the Choate be sure the tang is floated, may require sanding.

[Westcliffe01]

I would say that if it was working perfect for you to leave it alone, but clearly it is not. I have seen several of my savage actions that looked like the bottom of the action got "deburred" rather heavy handedly with a belt sander or something similar prior to being blued. Thus this happened at Savage... The result is that the action is not really cylindrical at all and therefore a metal bedding block is NEVER going to make proper contact.

The key thing here would be to scuff the bedding block with something to remove any surface contamination and enhance bonding, then degrease thoroughly and then apply a skim coat of devcon or similar bedding material on the bedding block. I would apply plenty of the bedding and allow it to squeeze out so that there are no gaps. Action screws should just be gently tightened just past hand tight, don't put any stress on anything ! Do the recoil lug at the same time. Tape on the forward face to create enough clearance to install it without drama.

[Luke45]

Thanks guys, sounds like a great weekend project hope it fixes it!

[Luke45]

I may have found the culprit, the part of the aluminum block where notch on the back I the recoil lug sits was very shallow and looked as if it was making contact before the action was making contact. Hope this solves problems. I will take west cliffs advice and bed the aluminum anyway even if this fixes the problem

[Westcliffe01]

For sure check that the tang is not interfereing. You only want bedding where the load is transferred at the 2 action screws and axially behind the recoil lug.

[CharlieNC]

Luke the various reports for bedding an alum v-block like in the Choate have not reported any benefit. Try repairing issues you see first, and then examine the witness marks on the receiver to see that these reflect good contact with the v-block. There should not be any clearance to for bedding compound between the receiver and the v-block, so you would need to remove metal to achieve that. Another primary spot to investigate is around the recoil lug; no contact except on the back face. You can add a layer of tape on the back of the lug to test the degree of fit, but again there is no room there to add bedding unless you remove metal. I did need to open the tang area on my three Choates, but then they shot great.

[Luke45]

Luke the various reports for bedding an alum v-block like in the Choate have not reported any benefit. Try repairing issues you see first, and then examine the witness marks on the receiver to see that these reflect good contact with the v-block. There should not be any clearance to for bedding compound between the receiver and the v-block, so you would need to remove metal to achieve that. Another primary spot to investigate is around the recoil lug; no contact except on the back face. You can add a layer of tape on the back of the lug to test the degree of fit, but again there is no room there to add bedding unless you remove metal. I did need to open the tang area on my three Choates, but then they shot great.
Thanks alot, will do. This one shoots great its just got some type of stress built up that is relieved by the first shot. hope the issue i found fixes it. I milled the notch out an 1/8 inch deeper and the action seems to sit down farther which tells me that it was definitly binding on that point and not having consistant contact with the v-block

[Luke45]

Problem solved. I milled out the aluminum block where the recoil lug notch was interfering and now cold bore shot is dead center of groups, thanks guys!