7mm SAUM AR

[stagpanther]

It is actually not too hard to disassemble and reassemble.

Like anything with the right gear it's not hard--just in my old age I have less enthusiasm fiddling with small parts.

[tangolima]

I don't have any special tool. Just punch and hammer.

Drive out the 1/16" roll pin. Very important, put the bolt face upside on the bench before pulling out the punch. The bench top captures the extractors and springs, or they will fly out. Reassemble trick is to use the punch as slave pin to guide the roll pin back in.

The rem 700 bolt, oh my goodness. Especially the extractor, I need to gather my best courage to take on that one, even with the special riveting tool.

-TL

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[tangolima]

Another funny observation. Now with the improved extraction and ejection, I went ahead to throttle back the gas, trying to further reduce the felt recoil. I found I could more or less shut the adjustable gas block all the way down, and the gun could still cycle ok. To add margin I opened it 1/8 of a turn. I remember when it was new, it required at least 2 full turns. I think the adjustment screw has been eroded down by the the hot gas. Sure I have increased the load by about 2%. Now the mv is approaching 3000fps.

-TL

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[stagpanther]

I just got an e-mail from xcaliber announcing their sale; seems they let you know you could be headed for trouble with bigger than usual x308 cartridges.

[tangolima]

Yup. I saw that when I bought the barrel. I love tinkering so went ahead. I probably would regret if I didn't. I have learned quite a bit while doing it. The AR platform makes it possible. Of course it would be harder without you guys' help.

I actually check that list every now and then to see whether they have another silly thing I can try.

-TL

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[Metal god]

Interesting…. that’s cool that they let you know that there may be issues but at the same time. That could have you looking at the left hand while the right hand is the problem . Which is kind of what happened with you, right . You were having extraction issues and I believe you were working on the gas block and trying to figure out the gas issue and it turned out to be your extractor . Do Did you think them posting that there may be gas issues slow slowed you down to look for other extraction issues ?

[tangolima]

I would say yes and no. The statement is their disclaimer that they can't be liable if it doesn't work out. I took the hint and order rifle + 2" gas length to lower the port pressure and dwell time. It might have saved me from some trouble. It is fair to say all the issues I have encountered were not their fault. I would run into those with or without their disclaimer.

-TL

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[tangolima]

X-caliber has similar barrel in 6.8 Western. It is relatively new chambering in .270 cal. Should I take out my monkey wrench on one?

-TL

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[stagpanther]

The 6.8 Western is a great cartridge IMO--I've shot it in a bolt gun and it is a very sensible interpretation of what the 270 WSM should have been IMO. But it too has the same "yer on yer own warning." Now, if you ask me--of the coolio options on that list that I would consider--it would hands down be the 25 creedmoor--one of the best cartridges ever developed for the .257 bullet in my experience. It shoots great--plus I already have 6mm and 6.5mm ARs in creedmoor and they are proven to work well in the AR10 style platform.

[tangolima]

.25 creedmoor eh? That should be much easier without the big fat brass. I probably can get the barrel cheaper somewhere else.

How's the old .257 Roberts? Nah the creedmoor is better. But not as funky as 6.8 Western. I will wait for the next sales and make up my mind.

The AR-10 is rated for .308's 60kpsi, I think. I need to watch out to keep the load mild.

-TL

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[stagpanther]

I bought my custom 25 creedmoor Shilen barrel through Northland Shooters Supply--like it so much I bought a second one as back up--probably do the same for my 30 BR barrel; but that's strictly for a shooter who loves getting into the weeds with making brass. NSS also works with Criterion who's match grade lapped barrels are excellent in my experience. It's a great fast cartridge and one that isn't going to fry out your bore.