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Gas block too tight?


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DPMS OEM SASS .750 gas block measures .7461 inside diameter... how tight is TOO tight? The Fulton/Criterion measures .7535...

I think the issue might be the combination.  DPMS SASS and a non-SASS barrel (the Fulton).  I'm pretty sure that if you're using DPMS SASS barrels, the only thing that's gonna fit will be a DPMS SASS gas block - and vice versa.  Those DPMS SASS-specific parts aren't gonna combine with anything else out there, and nothing is gonna combine with them.

I run a PRI gas block on my Fulton barrel (both are .936" parts) and there's no issue.  What fulton Criterion barrel do you have that's .750" ?  Is that the CroMoly lightweight one?

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I think the manufacturers of barrels and gas blocks state .750 and .936 as to keep it simple for everyone. If you look at the actual specs the sizes vary a bit but we never see this problem of fit. The problem is DPMS trying to change the game so their weapons are proprietary.

Unfortunately the problems don't show up until guys already have the DPMS hardware.


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Sure. I went with the heavy SASS block because the DPMS engineer had me convinced every other gas block would fail eventually because it being a .308... I'm looking at my 5.56 build and seeing a Troy low-profile slide right on and I'm saying, "maybe I should have bought two?" (Sure enough... the Troy for my 14.5 BCM build slides on the Criterion/Fulton without fanfare...)

Looking at the picture, do you think this gas block will under perform for the .308?


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I really try to be impartial about the various brands but man DPMS is making a strong case to put on the avoid list for those that like to tinker.

I did the SASS barrel and gas block just to see it all first hand. Fortunately I got a deal on the barrel that somewhat offset the stupid price of the gas block.

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DPMS ,I believe makes a good rifle for the most part ,but if I need any part ,I will be looking else where for it .They may think going proprietary is going to keep them in sales ,but they are wrong.

The good thing about the way it was before is, you could customize there rifles with what you wanted ,now it seems , you have to do it with there parts.

They may think its a good position for future sales ,but it not . Turns too many away.

Its like ,why not make a chrome lined barrel ? They would sell more if they did ,but don't have one ,why ?

Luckily ,other manufactures are making components ,that only DPMS used to make in the past .

I want to see more manufacturers make bolt carrier groups made out there though . Its  nice SI Defence is going to come out with one .

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When they first unveiled their SASS rifle, I saw alot of print about the special features.  One of the things they touted was a "tapered gas block attachment."  They don't pimp that so much anymore, but I still don't know what's "tapered" about it.  I'd imagine that if the gas block inn er diameter has taper to it, the barrel would have to have that same taper to lock up tight. 

Drew, was there anything "tapered" about the setup you picked up, either on the barrel or gas block?

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Two or three thousandths (0.002~0.003") difference in the taper would do it, and that wouldn't be visible without some precision measuring tools. 

I've got all kinds of measuring devices, if you want to send that gas block to me.  I'll whip up a detailed writeup with pics on the little monster. 

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Does anybody have one of these DPMS SASS gas blocks that would part with it for a week, so it could be measured out?  Or, does anybody need one of these things, and they're willing to buy it from me - if I'd order one, measure it, then send it out to you?  Either way will let me get the internal dimensions from the block.  <thumbsup>

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