16" Barrel with Rifle Length Gas
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Old 03-16-2011, 03:01 AM   #1
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Default 16" Barrel with Rifle Length Gas

So I have a barrel from Del-ton that is 16" with rifle length gas system. I've asked this question in other threads, but haven't gotten much solid info.

The upper is short-stroking with the intended BCG. If I put my Spike's BCG it cycles better, but still follows after last round and still occasionally short-strokes. I know that there isn't much dwell time on this set up (~4") and I am leaning towards that being the problem. (open to suggestions) The buffer in use was an A2 with standard components.

Question:

Can this be solved with a lighter buffer spring and/or buffer itself?

What else may be done to allow a full cycle with minimal pressure?

There is no leaking around the carrier key or gas block that I can see.

Thanks,
D

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Old 03-16-2011, 03:10 AM   #2
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Try the first 3 threads -
Technical and Professional discussion forums for enthusiasts of the M4 and AR15 family of weapons - Search Results for 16" Barrel with Rifle Length Gas

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Old 03-16-2011, 05:06 AM   #3
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Well I've done a bit of reading today and it seems the 2 options that permanently fix the issue and give you a reliable that can be used with any lower/buffer combo is 1.) Increasing the port size 2.) Blocking off the port and relocating it further inward and fitting a gas tube.

Both seem logical.

Anyone know how delicate increasing the port size is?

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Old 03-16-2011, 05:40 AM   #4
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Is Del-Ton any help? Seems ill advised for them to sell such a product in the first place unless they opened up the gas port enough. I'd lean on them and see what they can do.

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Old 03-16-2011, 03:49 PM   #5
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Contact Delton and ask how they set up their dissy. If its a complete Delton they have a lifetime guarantee.
You might try an AR-15 BCG instead of the heavier M-4 BCG. I would also check into lighter buffer spring.Or just a lighter spring with your heavier BCG. I would use plenty of lube to keep the BCG slick. Lube the 4 rails it rides for sure.
On the chart ive seen you have plenty of pressure but like you say the dwell time is real fast.
Have you tried different mags ?
Does your bolt lock back on the last round ?
Have you tried any .556 ammo? Full power ?

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Old 03-17-2011, 04:35 AM   #6
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Quote:
Originally Posted by MrMilspecer View Post
Contact Delton and ask how they set up their dissy. If its a complete Delton they have a lifetime guarantee.
You might try an AR-15 BCG instead of the heavier M-4 BCG. I would also check into lighter buffer spring.Or just a lighter spring with your heavier BCG. I would use plenty of lube to keep the BCG slick. Lube the 4 rails it rides for sure.
On the chart ive seen you have plenty of pressure but like you say the dwell time is real fast.
Have you tried different mags ?
Does your bolt lock back on the last round ?
Have you tried any .556 ammo? Full power ?
Well the good news is I picked up a "Fail Zero" BCG for another gun and the Spike's will now be freed up to ride in that rifle.

Anyone have any links for lighter buffers/springs???
All I am running across are standards and heavier, all the way up to H3. Nothing light.

I have tried different mags and was able to run the only full mags (all 30 rounds) with Magpul MOE mags.

I have also tried the 5.56 and the bolt still followed on the last round 2 out of 3 times. Using .223 the bolt always follows.

Del-Ton keeps sending me the automated "We have received your request and will have someone contact you" message 2 times now. . .

I'm off Friday, so I'm gonna try poking around at some gunsmiths to see if it is reasonable to increase the diameter of the port. It looks like from now on I'm gonna be solely ordering barrels from Green Mountain for baseline builds and White Oak for SPR types. Nothing but gold coming out of those places.
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Old 03-17-2011, 06:29 AM   #7
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Are any of your bolt carriers the AR-15 style? They weigh about 1/2 oz less than the M16 carriers. Dropping from an H buffer to standard carbine weight is about 0.9 oz so the carrier may be the next adjustment. You could also look for a light spring, something 10" or under. Don't know about lighter buffers and really why bother, this is a problem Del-Ton must correct!

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Old 03-18-2011, 01:12 AM   #8
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Yeah, I may have an AR-15 carrier in my Bushmaster Dissipator, but that gun runs so good as is, I don't want to mess with it. I have a regular carbine buffer and spring that I'm gonna try this weekend, maybe I'll have better luck than with the rifle buffer.

Del-ton won't respond of course and since it was only $150 barrel, I'm sure I can solve this economically. I really would rather spend the time doing it myself than messing around with them, unless they would do a flat out exchange for a barrel with carbine or mid-length system?

ANYONE KNOW WHERE TO GET A LIGHTER SPRING?

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Old 03-18-2011, 05:28 AM   #9
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Would be nice to get them to swap for a 16" middy. I don't know how practical rifle length is on 16".

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Old 03-18-2011, 05:32 AM   #10
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Quote:
Originally Posted by Quentin View Post
Would be nice to get them to swap for a 16" middy. I don't know how practical rifle length is on 16".
Doesnt seem very practical from the OPs experience w/ it.
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