6x47 Lapua in a lightweight semi rifle

[bustin]

Would the 6-6.5x47 Lapua have a chance as a competition rifle if the rifle weighed 4-5oz more than a comparable AR15? Meaning if an AR15 had the same length and profile barrel.
It should push 105 Bergers to 3050-3100 fairly easily.

 

[The Lawn Ranger]

First off, you would need to run it in an AR10 type rifle due to needed mag length.

Secondly, I am pretty sure you would have major feeding issues due to neck angle.

Go 6 Creedmoor in a large frame AR...

 

[bustin]

First off, you would need to run it in an AR10 type rifle due to needed mag length.

Secondly, I am pretty sure you would have major feeding issues due to neck angle.

Go 6 Creedmoor in a large frame AR...

A Creedmoor has the same shoulder angle and Hornady cases wont last near as long as Lapua. We're getting as few as 5 loading off the Hornady stuff and closer to 15 on the Lapua. Yes, we're using large framed ARs.

 

[JLR]

It's generally not the weight of the semi autos that keep them out of the running. It's usually that they're harder to shoot as consistently.

 

[bustin]

It's generally not the weight of the semi autos that keep them out of the running. It's usually that they're harder to shoot as consistently.

Are you saying all semi autos or AR10s? I understand they aren't going to be as accurate as my AICS. I keep getting calls from guys who think a semi may give them an advantage on some courses. I've sold a bunch of 6BRX barrels for AR15s, the 6x47 is almost 200fps faster.

 

[JLR]

I think that pretty much goes for all semi autos vs bolt guns. It's just easier to get the same performance/consistency out of a bolt gun. I've got a 6BRX in an AR15, have been fighting feeding issues though and just can't get the velocity I want out of it.

 

[bustin]

A 95 at 3200fps is just about max from a 22" BRX using N550. A 105 would probably drop to around 3000. 35.5Re17 will push a 105 Amax to 3040. The Gen 1 PRI 6.8 mags with the rounded front feed lips are the only ones that work without some tweaking. Try bending the mag spring front loop up to support the front of the follower and if running gen 2 or 3s round off the feed lips with a 1/4" radius.

 

[JLR]

I can get within maybe 50fps of those numbers without running a ridiculous amount of pressure using N550. I have Gen 1 PRI mags, but the problem I have is that with the 15 round mags I can only run around 6-7 before it starts to swell the mag. Also it has trouble with excess drag on the bcg with the first 1-2 shots out of a mag. After that it runs reliably, I just have issues with the first couple shots. Someday I'll get some time to play around with it and figure it all out. Too busy making a run at the top of the PRS at the moment though.

Getting back to your original topic, yes there is a place for a reliable high performance 6mm Semi-Auto. I think a straight 243 or 6 Creed is the way to go though as they run at a lower pressure and in theory may be a little less finicky in a gas gun.

 

[cjgemm]

This is how the 6 Creedmoor got its start. Ga Precision started it to run in their GAP10. It took off from that point to be the most popular Tactical cartridge in bolt rifles. Go figure.