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[ARCHIVED THREAD] - Over-gassed perhaps

Posted: 7/5/2010 6:23:56 PM EDT

My Iron Ridge DPMS build looks like it might be over-gassed. I'm ripping the rims off the case with FGMM175 ammo. When I rod the case it doesn't seem to take an inordinate amount of pressure to remove, and the brass looks more than fine on everything.

Gun is a 20" 308, Carbine stock/buffer/tube, rifle length gas.

Suggestions?

Posted: 7/5/2010 7:17:09 PM EDT

[#1]

rough chamber?

good/stiff exractor?

Posted: 7/5/2010 7:48:57 PM EDT

[#2]

Extractor is rock solid - so solid that it doesn't let go of the case - just rips it off.

I just burnished the chamber some - I'll shoot it again this coming week and see.

Posted: 7/6/2010 4:04:03 AM EDT

[#3]

What ammo are you running through it?

Posted: 7/6/2010 4:57:35 AM EDT

[#4]

What weight buffer?

Posted: 7/6/2010 5:55:09 AM EDT

[#5]

It's a carbine buffer. Pretty sure it's from a DPMS AP4.

Posted: 7/6/2010 6:23:54 AM EDT

[#6]

3.31 ounces it seems.

Posted: 7/6/2010 11:55:13 AM EDT

[#7]

Quoted:
3.31 ounces it seems.

You need a heavier buffer - 5.4oz.

Posted: 7/6/2010 12:26:59 PM EDT

[#8]

Anyone know the weight of the factory DPMS buffer? That would explain some of the issues.

I also ordered adjustable gas as I'm going to run a can later anyway.

Posted: 7/6/2010 5:24:53 PM EDT

[#9]

Quoted:
Anyone know the weight of the factory DPMS buffer? That would explain some of the issues.

I also ordered adjustable gas as I'm going to run a can later anyway.

Slash's chart has it at 3.4 oz.

Posted: 7/6/2010 6:08:21 PM EDT

[#10]

Not seeing gas as being the issue. Try different ammo. Your gun may not like that ammo. Doesn't mean your gun is broke. Did I mention to try different ammo?

EVERY GUN IS DIFFERENT.

Posted: 7/6/2010 6:57:15 PM EDT

[#11]

Quoted:

Quoted:
3.31 ounces it seems.

You need a heavier buffer - 5.4oz.

this

Posted: 7/6/2010 7:37:58 PM EDT

[#12]

Can you loosen the gas block and spin it where it partially covers the gas port and shoot it again? If that fixes the problem then you can buy an adjustable GB or sleeve the existing gas block passage.

Posted: 7/7/2010 6:18:27 AM EDT

[#13]

I tried multiple reloads and factory ammo types. All exhibited this behavior to some extent.

The issue has been located however - the gas port is out of spec. Measured it with pin gauges - its .105. Should be mid .08's to .090.

I'm going to run an adjustable gas block for now since a can is coming in the near future.

[ARCHIVED THREAD] - Over-gassed perhaps

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[ARCHIVED THREAD] - Over-gassed perhaps

[ARCHIVED THREAD] - Over-gassed perhaps