Quarterbore's Forums - Need Some Help

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As you can see by the user name I'm in Baghdad, in the BIG Litter Box...

While I've been here I have had the privledge to build and use a M-16 SBR (7.5") to be exact.

I am limited to the ammunition that is available here... can anyone tell me how to make my rifle "RUN" with the standard military ammunition???

Thanks...

:uzi2: :twoguns:

Well, we need more information...

Is this 5.56 (I assume but if it is 9mm whole different topic).

Where is the gas port (standard pistol location?) and where did you get the barrel?

What kinds of problems are you having? Does it work in semiauto or is problems only on full auto?

What stock and buffer are you using? With a shorty, you may need a heavier buffer!

Have you modified your extractor yet... many people with teh ultra shorties have extraction issues and I would need to look up the fixes as the shortest upper I use is 11.5-inches so I have not had any issues...

My site is not as active as many others so if you want mre oppinions, try posting on the M-16 forums at ar15.com as there will be many more guys there that have experience solving these issues but I will be glad to help as I can... (here or there)

The upper is a Model 1 Sales purchase... The problem is not an "everytime" thing, sometimes it "jams" after 4-5 rounds, other times works good... The stock is a Bushmaster colapsible with the standard spring and buffer.

A few changes you might want to consider...

This is an almost must have:

http://www.ar15.com/forums/topic.htm...f=218&t=150131

The D-Fender will help solve some of the exraction issues that seem common with the really short uppers.

Then I would suggest looking at a heavier buffer (say a 9mm buffer). This will help prevent the harsh bolt bounce common with shorties...

Let me know if these two things help... Model 1 Sales tends to be a "less expensive" manufacturer so I am curious why you bought there? http://www.cmmginc.com/ has a shorty upper that I would have much more confidence in if I was trusing my life to it:

See: http://cmmginc.secure-mall.com/shop/...368832&cat=43&

Quote:

CMMG M7SG 7.3 Upper

New 7.3" M7SG MedCon upper. The M7 SG upper features a unique secondary micro gas block that diverts gas early into a standard gas tube with a second hole. Gas diverted forward enters an expansion chamber, created by forward portion of the gas tube, making initial unlock “softer”. This saves wear and tear on the weapon. Since the gas port is further from the muzzle there is greater residual pressure to ensure increased reliability with ammo ranging from 45 to 77 gr. This upper is built around the M7 multi-role barrel and comes with a four rail free float handguard and is complete with bolt, carrier and charging handle. CMMG semi auto bolt carriers have the shrouded firing pin to protect against hammer wear. Upper receivers are "T" marked and include extended feed ramp cuts. Features include medium contour barrel, 11 degree recessed target crown, chrome-lined 5.56mm chamber and bore, 1/7 twist, parkerizing under “F” marked forged front sight base and magnetic particle testing on every barrel. When ordering with optional gas block, barrels will not be drilled for taper pins. Barrel is marked CMMG MPC 5.56 NATO 1/7.

The reason for the Model 1 buy was it is inexpensive...

A few notes: I placed the upper on my Bushmaster M4 and it shot great. and it is accurate. However, we are looking at an extra gun. The lowers that are available are old (1960's) M-16 versons.

I called Bushmaster and they have recommended the same about the buffer and D-ring... Both are on order as I type, so we'll see what it does.

Thanks for the help...

:uzi2: