Colt pencil barrel and a suppressor

[UPSguy]

I have come across a NIB Colt LE6933 thanks to BigBore. When I told him to get it for me I did not realize it had the lightweight pencil barrel. My question is this: is the pencil barrel strong or stiff enough if I plan on having a suppressor attached 90+% of the time? OK, I have my flame retardent suit on now so I am ready for the responses.

[rob_s]

I'll be testing that theory very soon. I'm leaning heavily towards the Ops 15th model because it is supported in two places on the barrel so it should be less prone to causing barrel deflection.

[K.L. Davis]

Are you asking if the weight of the can can bend the barrel? I wouldn't worry about it unless you have a really freaking heavy suppressor. Think how much force is put on the barrel by a strong sling hold, or even just grabbing the handguard and wrenching?

Sure a thin barrel will "droop" before a heavy one will if you run them hard enough, but then you've got other problems to worry about...

The biggest concern that I would have is the POI change may be more pronounced on the thinner barrel, but if you are going to leave the can on, no big deal.

[Akoni]

According to a bud with a Commando and an m4-2k, he doesn't get more that .5 moa shift but not sure how that would hold under sustained fire conditions.

[USMC03]

My experiences from another post on point of impact shift with a suppressor (also remember each different barrel an suppressor set up will have different end results, these are just my experiences........the shorter and / or the heavier the barrel the less impact shift you will see):


There is only 4 oz of difference between the Govt profile barrel and the M4 SOCOM barrel (you can tell a *slight* difference in weight). A pic of the M4 SOCOM barrel can be seen here:

www.ar15.com/forums/topic.html?b=7&f=22&t=284588


The reason I went with the Colt M4 SOCOM barrel (heavier profile) is due to point of impact change when using a suppressor. The shorter and stiffer the barrel is, the less point of impact change you will experience once the suppressor is installed on the barrel.

When using a suppressor, you will experience a point of impact change. All of my guns are sighted in at point of aim / point of impact at 50 yards. Here is what I expereince using the M4-96D and the G5 suppressor using both 16" M4 profile barrel and the heavier Colt 14.5" SOCOM barrel:


When I was using the M4-96D in conjunction with the Colt 16" M4 profile barrel, my point of impact was low and to the right (between 4 and 5 o'clock) and approximately 4" low at 50 yards.

After the M4-96D was converted to the G5, the G5's point of impact shifted to approximately 3" low at 6 o'clock using the same barrel at the same distance (host guns were 2 Colt LE6920's).

After switching to the Colt 14.5" M4 SOCOM barrel with the Gem-Tech G5, the groups are only approximately 1/2" between 5 and 6 o'clock at 50 yards.

Semper Fi,
Jeff

[UPSguy]

My concerns were based on an email exchange between John Noveske and myself about a SBR build using his 12.5" barrel. He has 3 different profile weights and advised me to stay away from the lightest if I was going to use a suppressor most of the time. Since he charges the same regardless of the weight I felt he was giving me an honest opinion not trying to sell a more expensive barrel. Since a Colt pencil barrel is smaller in profile than the lightweight Noveske I added 2+2 and may have come up with 5. Thanks for the answers.

[S-1]

The biggest concern that I would have is the POI change may be more pronounced on the thinner barrel, but if you are going to leave the can on, no big deal.

Yep.

Here's another route you can take. Sell or trade the 11.5" pencil barrel for a Colt 14.5" SOCOM barrel. Send the upper along with the SOCOM barrel to Randall at AR15Barrels and have him chop it down to 10.5". You'll have a heavier profile barrel along with a shorter length and that will result in less POI change.

IIRC... LMT used to ship their 10.5's with a lightweight profile barrel then later switched to a "medium" profile for this reason. Someone correct me if i'm wrong.

[bigbore]

If the POI shift is more than 1.5" at 50yds with your surefire can installed, I'll trade you for any barrel you want. As Itold you, as usual your losing sleep over nothing;)

[UPSguy]

As Itold you, as usual your losing sleep over nothing;)
Yes I do. Speaking of that I am going to try and go to sleep now:D

[rob_s]

Those 6933 (or 0933) barrels are fetching a prett penny over at SAW ($495:eek: ), so I wouldn't worry too much if you want to "upgrade". I know SAW is generally awefully proud of their stuff, but the 6933 barrels would still appear to fetch a premium.
http://www.specializedarmament.com/products/BARREL_FRONT_SIGHT_ASSY_R0933_1_7_LWT_11_5in_CHROME_LINED-70-4.html