AK Arm Brace or Stock? Arm Bar vs Stock Guide

Our best AK arm brace setup is the 9-inch AB-9R arm bar with the AB-BS stabilizer. It is the only JMac rear that can be set up as an arm bar or, with a folding buttplate sold separately, as a stock-style setup. Pick it if you want one rear that can change roles. Pick a skeleton, triangle or tube stock if you want one fixed shape. All of them ride the same JMac mounts. This guide covers fit and setup, not legal classification.

What is the JMac arm bar?

The AB-9R is a 9" arm bar machined from 7075-T6 aluminum with a Type 3 hardcoat. The arm bar weighs 3.5 oz. It has a built-in cheek riser, is drilled and tapped for more risers, and adjusts in height. The AB-BS stabilizer bolts to its rear and replaces the earlier AB-BA adapter. It comes in black, green and tan. Green and tan are limited runs.

Is the JMac arm bar a folding arm brace?

The folding comes from the mount, not the arm bar. The SM-5.5 folds on 5.5mm AK rears. The SM-1913 is fixed. JMac's folding 1913 mechanism is a separate part.

How do AK arm bars and stocks compare?

Which AK rear gets my cheek on the optic?

Any of them, once you add the right riser. The arm bar, the SS-8RP and the TS-9RP all take CRIM risers in 1/4", 1/2" and 3/4". The CRSU adjusts to three heights if you swap optics.

What mount do I need for an AK arm bar?

It depends on your rear. Every one of these rears runs on a JMac SM mount:

• SM-1913 for a 1913 rear rail, or for a host fitted with a JMac RSA adapter.
• SM-5.5 for 5.5mm folding AK rears.

The arm bar is our recommended setup for hosts with a 1913 rear rail or a JMac RSA adapter.

Arm bar and stock fit table

The arm bar, stocks and risers attach to SM mounts per the JMac catalog. Fit and availability are separate. This guide covers fit and setup, not legal classification. Check current federal, state and local law for your configuration before you build.

Can I switch from an arm bar to a stock later?

Yes. The mount stays the same, so going from an arm bar to a skeleton stock is a swap of the rear only.

FAQ

What is the difference between an arm bar and a stock?

JMac's AB-9R arm bar is a modular rear. With the AB-BS stabilizer it rests on your forearm, and with a folding buttplate (sold separately) it can be set up as a stock-style rear. A stock has one fixed shape.

Which is lighter?

By the product pages, the AB-9R arm bar is 3.5 oz, the ST-7R tube is 3.90 oz, the TS-9RP is 5.10 oz and the SS-8RP is 5.36 oz.

Do JMac stocks have a cheek rise?

The SS-8RP and TS-9RP have a 0.275" built-in rise. The arm bar has a built-in riser. All three take 1/4", 1/2" or 3/4" CRIM risers.

What mount do I need for an arm bar?

The SM-1913 for a 1913 rear rail or a JMac RSA adapter, or the SM-5.5 for 5.5mm folding AK rears.

Can I switch from an arm bar to a stock later?

Yes. Both use the same JMac mount, so only the rear changes.