PDA

View Full Version : Photos: "Government" Barrel vs. "Pencil" Barrel Weight Difference



butler
06-01-2018, 17:51
I'm new to AR-15 builds, so please bear with me if I make any mistakes.

That being said, for those who are curious about the actual weight difference between a "government" barrel profile (also known as an A2 barrel profile) and a "pencil" barrel profile (also known as an A1 barrel profile): (this picture/schematic isn't mine; I found it in a Google search, but I don't recall where)
https://i.imgur.com/LDn4k0d.jpg

I did an apples-to-apples comparison between two barreled upper assemblies from Palmetto State Armory (PSA). Both have 16" barrels with a midlength gas system; both have rear back-up iron sights (BUIS), bolt carrier groups (BCG), charging handles (CH), front sling swivels, and muzzle devices removed.

I know it's an informal test at home (using a baby scale, no less), but the government/A2 style barreled upper assembly came in at 2 pounds, 13.5 ounces (sorry about the glare):
https://i.imgur.com/z7yamoH.jpg

In contrast, the pencil/A1 style barreled upper assembly weighs 2 pounds, 8.0 ounces (again, sorry about the glare).
https://i.imgur.com/IV37Q0X.jpg

The weight difference may seem negligible, but it really does seem to assist with handling/weight perception.

But it could be all psychological....

SA Friday
06-04-2018, 21:15
If I put 5 ounces in your hand and tell you to hold it out for as long as you can, then I do the same thing but the weight is on a two foot stick. With one is more fatiguing faster? The one on the two foot stick. It's not just the weight, it's where the weight is. It comes down to use and the shooter's physical capabilities. The thicker the barrel the more stiff it is and the less harmonic movement there is while shooting. It lowers the standard deviation from point of accuracy. It also dissipate heat faster. The thinner the barrel, in general the less accuracy you will see and it will get and stay hotter for longer but it's easier to shoot in fatiguing positions and carry for long periods.

ben4372
07-20-2018, 22:53
Quite a while back I built a pencil barrel with a minimalist stock and an A2 upper. I still use it as a light weight option. Everyone is amazed at how light it is. Granted I don't do mag dumps and accuracy is not spectacular, but it is easy to carry.

SAnd
07-20-2018, 23:05
I hear that the pencil barrels don't make very good pry bars. That may be something to consider if your beer bottles have stiff caps on them.

ben4372
07-21-2018, 20:23
I was wondering why the changed the diameter of the part sticking out of the guard, and not the part in the middle. Maybe harmonics? Or is it to make it appear more substantial.

Mazin
07-21-2018, 20:51
I was wondering why the changed the diameter of the part sticking out of the guard, and not the part in the middle. Maybe harmonics? Or is it to make it appear more substantial.

Little more weight to combat muzzle jump? That's the only thing I could come up with.

SAnd
07-21-2018, 22:47
I was only semi-joking. Read the final couple posts and decide for your self if it can be true.

https://www.ar15.com/forums/ar-15/-/12-573125/?

ben4372
07-22-2018, 22:32
I was only semi-joking. Read the final couple posts and decide for your self if it can be true.

https://www.ar15.com/forums/ar-15/-/12-573125/?

Thanks for the link. I especially like the "out of spec caused by a burr". I still find it silly. I would think the engineering people would have been a little sharper. Everything I've bent, bends in the middle.

battlemidget
02-16-2019, 18:37
I have a Faxon gunner (normal to the block and thin to the tip), the 14.5 w/pinned brake. I can tell you it does heat up quicker, but it cools down quicker too, like ~2 minutes it's cooled off significantly. For under 300m it's awesome. Slightly gassy, .081