6x47 vs 6XC gas gun

[mac86951]

Ok; yes lots of research so far; but two questions:

What is your typical COL for either cartridge with 107s?

Anyone had luck with JP high pressure bolt and the small primers of 6x47?

Gas gun, I'm leaning toward 6XC II for longer barrel life than 243 or super LR; and 105/107 at mag length for sure. Planning a 1:8" twist; and hopefully the 75hp varmints will work fine too.

6x47 could be fine too; hesitant due to small primer with potentially sloppy AR bolt firing pin hole.

-Mac

 

[JLT]

Just curious - Why the concern with barrel life? From one perspective, there is no easier re-barreling job than an AR.

 

[mac86951]

Just curious - Why the concern with barrel life? From one perspective, there is no easier re-barreling job than an AR.

True; but I don't want to be rebarreling mid season with something like 243. Add to that deep seated 107s or 115s has me looking at the other 6mms

 

[msalm]

I built a couple X47 Lapua rifles on the AR10 platform. At the time I used the Armalite bolt as it has a smaller diameter firing pin and it worked well with no cratering issues. You'll have problems with the DPMS larger diameter fp hole bolts.

 

[mac86951]

I built a couple X47 Lapua rifles on the AR10 platform. At the time I used the Armalite bolt as it has a smaller diameter firing pin and it worked well with no cratering issues. You'll have problems with the DPMS larger diameter fp hole bolts.

True, I plan on using a JP high pressure bolt / pin combo at a minimum.

 

[Grimstod]

The 47L has great brass and that would swing me. Some have had problems with it being load finicky but that I think is mainly neck turning issues. But hay I do not have a ton of experience here. XC will be easer to do since there is factory brass.

 

[mac86951]

The 47L has great brass and that would swing me. Some have had problems with it being load finicky but that I think is mainly neck turning issues. But hay I do not have a ton of experience here. XC will be easer to do since there is factory brass.

Yes; and either way there's some tender loving care applied to the brass I'll be forcing thru the air and into dirt; concrete, posts, neighboring shooters, etc... I may go a third route with 6SLR for Winchester 243 brass may hurt less to lose.

 

[dcali]

I would do a .243 just to avoid running expensive brass through a gas gun.

 

[woodnut]

MSalm built me one sweet AR10 in 6x47 Lapua! I am now trying a load of VVN560 with 105 A Maxs. First group with this load went .328! I had been playing with weights from 87 up to 95s, but the 105s seem to have the best potential for long range shooting. I think the twist is 9, BTW.

 

[Tommie]

Don't get your hopes up real high. The few grains difference between the .243 Win and the others you're looking at isn't going to make a huge difference in barrel life. Yeah, the 20 degree shoulder and short neck on the .243 is a little harder on the throat. Just keep in mind that any of the cartridges you're considering have considerably more capacity than the BR family of chamberings.

 

[Kurz]

Gas gun, I'm leaning toward 6XC II for longer barrel life than 243 or super LR; and 105/107 at mag length for sure. Planning a 1:8" twist; and hopefully the 75hp varmints will work fine too.

6x47 could be fine too; hesitant due to small primer with potentially sloppy AR bolt firing pin hole.

We are fortunate to have a better selection of 6mm cartridges these days. You can pretty much pick your level of performance and run with it knowing that you still have good brass and the potential for fine accuracy.

I think that you should also consider the 6mm Creedmoor as well. This and its parent cartridge the 6.5 Creedmoor both perform admirably in an AR or gas gun format. Being shorter like the 6x47 and the XC, you can seat bullets out further without hitting the limits of the magazine feed. Then too, we now have the Lapua small firing pin hole 6.5 Creedmoor which can be necked down and used. Yes, the JP is a nice solution.

Remember to select a gunsmith who has a great working knowledge of the gas port sizes, gas port placement and the gas tube lengths.

Regards.