Bushed firing pin requirement for Accuracy International Coopermatch 6.5x47L?

[FatBoy]

I am a couple weeks away from having an 8 twist Krieger screwed onto my AI Coopermatch and chambering it in 6.5x47L, however I have been contemplating changing gears do the in inability (or maybe lack or desire) to have the firing pin bushed due to the rarity of these rifles and inability to get parts, specifically another one of the pin in six lug bolt heads. I do not want to have to have one made as that will cost more than a new action.

The chances of finding anyone who has chambered a Coopermatch in 6.5x47L is slim, so for those who have chambered standard AI rifles in this caliber, was primer piercing an issue?

 

[FatBoy]

Looks like I'm going go be a guinea pig. Decided to borescope my pull offs and knock the threads off the best one to test. Sucks chambering a barrel that has 600+ 6.5x284 through it but that's better than loosing 2" of a brand new Kreiger 6.5 medium palma tube.

Stay tuned. Could be 4-6 weeks.

 

[kreiert]

I'm also interested to see how this project works out as I also have a AI Coopermatch.

 

[FatBoy]

Maybe we can arrange to put one of my old Border barrels on that Coopermatch you have for testing? ???

 

[kreiert]

I'm thinking the best thing to do with my AI Cooper Match, is to turn it into what it was always meant to be.
A Palma Rifle............................................................. Tim

 

[FatBoy]

That rifle was originally designed as a 300m rifle but I feel the poke...... next you'll be telling me I need to shoot a (gasp) service rifle.

 

[FatBoy]

Well, 35 rounds loaded up to test this rifle. 8.5 twist Border with roughly 350 rounds down the pipe before the set back, rechambering and recrown. Going to ORSA Sunday to shoot it in the 1x1000 Big Ed's match.

Lapua Virgin over a K&M mandrel to square the necks
38.0gr Varget
CCI 450m
130VLDs .012" in the lands

Figure this is good for 2900fps out of a 28.5" barrel. Load should be light enough and primer cup rugged enough to give it max chance to NOT pierce any primers. without load testing, I went with load recommended to be by a gent who I watched shoot 200-24x at 1000y. Well, .5gr less than his load. FagMag will be in the car just in case.

 

[FatBoy]

Put six rounds through it. No pierced primers but it's cratering and sweeping the case heads pretty good. I'm encouraged and think maybe rl15 or h4350 may get the job done.

 

[FatBoy]

I put about 90 rounds down the pipe yesterday. 38gr varget with 130vld, 36.5gr varget and rl15 as we as 37gr varget and rl15 under 136 Lapuas, 140 Berger Hybirds and 142SMKs. No issues with primers of pressure at all yesterday. No swiping on the brass, just some cratering around the pin but otherwise the primers were nice and round.

Seems the 450m with varget had the best SD/ES and group average was best with a 142 seated .0015" off.

I may try h4350 next time Tim has time to set up the chrono and I can get a day off work. I sure would like to get another 100 fps out of it if I can hold the accuracy. 2730-2740 seems a touch slow. As it ks, i'm taking this load to Oak Ridge tomorrow tons how bad giving up .8moa in the wind is going to hurt.

 

[FatBoy]

Took it to 1k yesterday with 142SMKs and 140 Berger Hybrids. It was respectable, but cetainly no 6.5x284. There was less fatigue after 85-90 shots in the heat. (85-92°f).

Only issue I had (that wasn't self induced) was it had some serious bolt face sweep and hard extraction on the first six or seven roujds. To the point of pealing a sharp ridge on the case head with the ejector hole. This is the second time this setup has had higher than normal pressure on a clean barrel. I refuse to shoot moly, so i'm going to have to figure out WTF is going on. I can't be tossing 6-10 sticks of brass in the trash every time I clean. Guess I could see how long it will shoot before it needs cleaning? Or send 6-7 light load foulers into the berm, but that creates a safety issue.