Gunsmithing Carrier Weight System, goig to make my own have a

[Heman]

Going to make my own Carrier Weight System. Question I have is the Tubbs CWS with tungsten insert is 4.05 oz or 114grams. How heavy can you make one and still have it function?

Plan was to use tool steel and make it 2.75" long which looks to be max length and not interfere with the trigger, then bore the center out and fill it with lead to get the weight up.

Rifle will be for an AR-10 and thinking about making a heavier one. Load is 45gr of Varget and a 175gr SMK in the .308 upper and a 142gr SMK and 45gr of H4831SC for the .260 upper.

I know I'm going to be limited since my lead core won't be as dense as tungsten. Any advice would be appreciated, thanks in advance.

 

[Don Black]

Re: Carrier Weight System, goig to make my own have a

I did this a few years ago for my space gun, in stainless.
It worked good for a while, but after a few hundres rounds the rim sheared and the weight flung forward into the carrier & jammed the whole upper to the point that I had to pull both takedown pins to separate it from the lower.
Of course, this had to happen in the middle of a match. Lots of cussin' & fussin'.
The problem was the rim thickness. Too thick & you won't be able to close the upper/lower assembly. Too thin, it shears sooner or later. most steels just aren't tough enough to withstand the inertial trauma involved, and will eventually fail, a lesson learned after the fact.
My guess is that might be why Tubbs selected tungsten, a much tougher material, for his weights.
Your tool steel might work, if you get the right heat treat.

 

[Hellbender]

Re: Carrier Weight System, goig to make my own have a

Also, If you want to add weight, make sure the buffer is full of tungsten weights and not mostly aluminum spacer, I don't remember the exact layout inside the AR10 buffer, pull it apart and look.

Buy a cheap AR15 buffer and steal the tungsten weights and rubber washers out of it, it's cheaper and easier than just buying the weights.

A better route than all the extra weight banging around (which has consequences, most not good) is an adjustable gas block to properly adjust the amount of gas needed to operate the weapon, speed it up or slow it down as you see fit.

 

[Heman]

Re: Carrier Weight System, goig to make my own have a

I've ran a Tubbs CWS in my AR-10 for about 3 years for XTC matches and LR (when I shot it for this) and my brother in his AR-15 for service XTC. Haven't experienced any shearing issues but thanks for the heads up. With my Tubbs CWS in any of our rifles I need to pull both pins to seperate so I think I may make the head a little over 0.080" to insure it doesn't shear. However adjusting the gas block does sound like a good idea. Got some time so think I'll play around.

 

[Don Black]

Re: Carrier Weight System, goig to make my own have a

I don't have an adjustable gas block on my (Armalite)space gun, but was able to shift it forward to partially occlude the gas port to reduce blowback pressure to slow down the bolt velocity.
It pretty well achieves the same purpose as the carrier weight.

 

[memilanuk]

Re: Carrier Weight System, goig to make my own have a

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bermshot</div><div class="ubbcode-body">The problem was the rim thickness. Too thick & you won't be able to close the upper/lower assembly. Too thin, it shears sooner or later. </div></div>

One solution that works with the original CWS weights is to have some nice machinist counter-bore the back of the bolt carrier so the weight sits just below flush with the end of the carrier. Problem solved and you don't have to mess around with a too-thin rim on the weight.

 

[toolmaker]

Re: Carrier Weight System, goig to make my own have a

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: memilanuk</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bermshot</div><div class="ubbcode-body">The problem was the rim thickness. Too thick & you won't be able to close the upper/lower assembly. Too thin, it shears sooner or later. </div></div>

One solution that works with the original CWS weights is to have some nice machinist counter-bore the back of the bolt carrier so the weight sits just below flush with the end of the carrier. Problem solved and you don't have to mess around with a too-thin rim on the weight. </div></div> I have been doing it this way for years. I counter bore the carrier .125 deep to a diameter of .725 I make the weights from Elkonite which is a tungsten copper used for making resistance welding electrodes. I normally use a 2.5 oz. weight when shooting 68 gr. bullets with 23.8 gr. of Varget out of a 20in. Krieger barrel. I have gone as much as 3.0 oz without any issues but went back to the 2.5 oz weight.

 

[Don Black]

Re: Carrier Weight System, goig to make my own have a

Fookin' genius, guys!
Reckon I spent too much time looking for a complex answer to a simple problem.

Gonna have to do it!

 

[badbot]

Re: Carrier Weight System, goig to make my own have a

rc 50-53 AREA is very tough and not brittle for good S7 like tool steels.
took a chunk out of a sledge hammer face with minium distortion to my tool.
YMMV

 

[Heman]

Re: Carrier Weight System, goig to make my own have a

Well I had some downtime so I made two. Both are 2.75" long which fit the AR-10 bolt just fine. Bored a cavity in one 1.5" long and the other 2.5" long. By my caclulations the longer one should have a weight of 4.7 ounces total when filled with lead, and the other will be around 4.1 or 4.15 oz. acording to my calculations. Haven't added the lead to it yet so won't know exact weight till I'm done.