rifle upper on a carbine lower. any issues?

[mattjmcd]

Should I expect any issues if I put my 20" upper on my carbine-specific lower? I run a Magpul CTR. Will the different buffer setup make any different in terms of overall dynamics with the operation of the action?

[Saginaw79]

You should be good, though if you run a heavy buffer it could cause cycling issues

Other than that I dont see a problem

[NickB]

You should be good to go, but I suggest running an H2 buffer if you have the option.

[Iraqgunz]

Are you talking about a rifle (20 in.) upper on a lower with a telescoping stock and carbine sizespring and buffer? If so, I will pass on some info that was given to my Colt class a while back by Ken at SAW. Apparently an armorer for an agency in Arizona did that and they started experiencing malfunctions. They called him to say what POS's the Colts were and he went out investigate. Once they switched back to the original configuration the problems went away. He advised us not do it.

[mattjmcd]

Originally Posted by Iraqgunz

Are you talking about a rifle (20 in.) upper on a lower with a telescoping stock and carbine sizespring and buffer? If so, I will pass on some info that was given to my Colt class a while back by Ken at SAW. Apparently an armorer for an agency in Arizona did that and they started experiencing malfunctions. They called him to say what POS's the Colts were and he went out investigate. Once they switched back to the original configuration the problems went away. He advised us not do it.

That's what I am talking about. I live in CA and we are only allowed to have lowers from before our ban. I have 1 registered lower. I would like to be able to go back and forth between my 20" upper and my 16" carbine upper. The LOP of the carbine stock is so nice, that I'd rather not go back to the A2-style stock unless it was absolutely necessary.

[NickB]

Originally Posted by Iraqgunz

Are you talking about a rifle (20 in.) upper on a lower with a telescoping stock and carbine sizespring and buffer? If so, I will pass on some info that was given to my Colt class a while back by Ken at SAW. Apparently an armorer for an agency in Arizona did that and they started experiencing malfunctions. They called him to say what POS's the Colts were and he went out investigate. Once they switched back to the original configuration the problems went away. He advised us not do it.

That is most certainly not Colt's position on the issue. In fact, Colt Canada manufactures the C7A2 rifle for the Canadian military in the exact configuration in question (20" rifle length gas system with carbine buffer system using H2 buffer). If you use the wrong buffer weight you may experience some bolt bounce and possibly some malfunctions, but the overall weapon reliability is unaffected if an H2 carbine buffer is used.

[tiger seven]

This has run fine for me (vintage Colt SP-1 upper) using both CAR and H buffers.



Derek

[Skintop911]

Originally Posted by NickB

That is most certainly not Colt's position on the issue. In fact, Colt Canada manufactures the C7A2 rifle for the Canadian military in the exact configuration in question (20" rifle length gas system with carbine buffer system using H2 buffer). If you use the wrong buffer weight you may experience some bolt bounce and possibly some malfunctions, but the overall weapon reliability is unaffected if an H2 carbine buffer is used.

The H2 fixed a batch of LESO M-16A1s retrofitted with collapsible stocks.

[NickB]

Originally Posted by Skintop911

The H2 fixed a batch of LESO M-16A1s retrofitted with collapsible stocks.

Bingo. It's not a problem if done correctly.

[live2offroad]

This is just a dead sexy awesome looking rifle. Man I love that upper style, comes from growing up in the 70's I guess..
-Peter

Originally Posted by tiger seven

This has run fine for me (vintage Colt SP-1 upper) using both CAR and H buffers.



Derek

[KevinB]

As stated by NickB -- the H2 was found to run the best of all buffer weights over a range of barrel lengths.

The C7A2 is issued with a 20" upper - and some units get also a 16" upper (SFW) and others a 10" CQB upper as well.

The H2 worked well throughout those lengths

[Iraqgunz]

That may be true, but since Ken has taught their course for about 10 years I trust what he observed. If you say that an H2 buffer fixed the problem that's fine. but, personally I try noy to dick with stuff that works.

Originally Posted by NickB

That is most certainly not Colt's position on the issue. In fact, Colt Canada manufactures the C7A2 rifle for the Canadian military in the exact configuration in question (20" rifle length gas system with carbine buffer system using H2 buffer). If you use the wrong buffer weight you may experience some bolt bounce and possibly some malfunctions, but the overall weapon reliability is unaffected if an H2 carbine buffer is used.

[NickB]

Originally Posted by Iraqgunz

That may be true, but since Ken has taught their course for about 10 years I trust what he observed. If you say that an H2 buffer fixed the problem that's fine. but, personally I try noy to dick with stuff that works.

I believe that Ken observed these malfunctions, but I assume there is something more to the equation. For starters, I doubt they dropped the appropriate buffers into the weapons when the stocks were changed.

I have conducted extensive research on this subject, done high speed video, live fire testing, etc. The only malfunctions I observed were when using a standard weight carbine buffer and stiff carbine spring, and even those were rare. Colt Canada and the Canadian military have done testing on the C7A2 rifle including temperature extremes, environmental factors, altitude, ammunition, etc., and have found no negative effect on reliability when used with the H2 carbine buffer.

I'm not calling Ken a liar, but I don't think his information is as complete as it should be to make that type of determination.

[Skintop911]

AC content is built around the lowest common denominator attendee, with a hearty dose of risk-management in mind. Getting guys to understand that Tab A goes in Slot B seems to be a chore at times. Imagine teaching all the variables in balancing components in gas guns to Joe Armorer, and how much time it would take to do so. He could be given a chart or TO, but he should understand.

Ken said the same thing in my AC years ago, but helped those that needed it in "evening session."

[Bimmer]

Originally Posted by mattjmcd

TI live in CA and we are only allowed to have lowers from before our ban.

This is false.

It's easy enough to get an OLL (Off-List-Lower) now. Poke around calguns.net

Ben

[KevinB]

All H2's

Diemaco/Colt Canada did exhaustive testing.












Usually I will agree with Ken Elmore on M16FOW issues -- but on this one its not correct.

[DocGKR]

There are NO problems with using a rifle length upper on a carbine lower, as COLT itself has proven with the COLT manufactured, tested, and approved C7A2 that comes from COLT with a carbine stock, H2 buffer, and standard 20" barrel upper.

[Iraqgunz]

Skintop,

I agree the same way the military has to teach to the lowest monkey denominator.

Originally Posted by Skintop911

AC content is built around the lowest common denominator attendee, with a hearty dose of risk-management in mind. Getting guys to understand that Tab A goes in Slot B seems to be a chore at times. Imagine teaching all the variables in balancing components in gas guns to Joe Armorer, and how much time it would take to do so. He could be given a chart or TO, but he should understand.

Ken said the same thing in my AC years ago, but helped those that needed it in "evening session."

[Iraqgunz]

Thanks for the insight.

Originally Posted by NickB

I believe that Ken observed these malfunctions, but I assume there is something more to the equation. For starters, I doubt they dropped the appropriate buffers into the weapons when the stocks were changed.

I have conducted extensive research on this subject, done high speed video, live fire testing, etc. The only malfunctions I observed were when using a standard weight carbine buffer and stiff carbine spring, and even those were rare. Colt Canada and the Canadian military have done testing on the C7A2 rifle including temperature extremes, environmental factors, altitude, ammunition, etc., and have found no negative effect on reliability when used with the H2 carbine buffer.

I'm not calling Ken a liar, but I don't think his information is as complete as it should be to make that type of determination.

[NickB]

Originally Posted by Iraqgunz

Thanks for the insight.

Any time. This is actually a big problem for smaller-stature soldiers and women, especially when using body armor.