9mm Non-dedicated Rig

[1168]

So I will need a spacer if running a standard carbine buffer tube, spring and h3? Committing to the BKing BCG at 14.6oz I believe…. I guess I will find out.

Maybe. It’ll be fine, unless you break a bolt catch or whore out that pocket in the lower. I’m not sure how common that still is.

Do flash hiders work on PCC's? Specifically 7" barrels?

Yes. I’ve used a Griffin 3-prong on an 8.5” barrel 9mm. An adequately long silencer would help, also. Of course, the flash without one isn’t huge (consider the humble Glock), and a 1.25”-1.75” longer barrel would be just as reasonable a choice compared to any 9mm muzzle device. Powder or ammo selection goes a long way. For example, Titegroup is thermonuclear in comparison to CFE-P.

[Screwball]

Desired result is a lower that will run all 3 calibers with minimal swapping of lower parts.

Just a heads up, but a lot of people have attempted that… you’ll end up getting additional lowers to make them individual guns. Nature of the beast.

Shy of a SBR or MG lower, it’s not hard to buy 2 stripped lowers and build to complete as you put money away. If it’s a pistol lower, without any plans to Form 1… even easier.

[HKGuns]

Deleted, off topic.

[prepare]

Yes. I’ve used a Griffin 3-prong on an 8.5” barrel 9mm. An adequately long silencer would help, also. Of course, the flash without one isn’t huge (consider the humble Glock), and a 1.25”-1.75” longer barrel would be just as reasonable a choice compared to any 9mm muzzle device. Powder or ammo selection goes a long way. For example, Titegroup is thermonuclear in comparison to CFE-P.

Wonder if there would be any significant difference with this device vs a plain 3 lug adapter?

https://angstadtarms.com/product/3-lug-flash-hider/

[CrowCommand]

Maybe. It’ll be fine, unless you break a bolt catch or whore out that pocket in the lower. I’m not sure how common that still is.

Thanks, what pocket are you speaking of? Just so I can keep an eye on things.

[CrowCommand]

Just a heads up, but a lot of people have attempted that… you’ll end up getting additional lowers to make them individual guns. Nature of the beast.

Shy of a SBR or MG lower, it’s not hard to buy 2 stripped lowers and build to complete as you put money away. If it’s a pistol lower, without any plans to Form 1… even easier.

I am aware of this phenomenon… no NFA in my state, so this was a god reason to have a second pistol lower on hand. Should be alright now to just swap uppers as needed, but we’ll see.

[1168]

Wonder if there would be any significant difference with this device vs a plain 3 lug adapter?

https://angstadtarms.com/product/3-lug-flash-hider/

not sure, but just looking at it, I suspect that it would help disperse some flash, probably even reduce it overall. Seems like most decent 9mm devices do help.

Thanks, what pocket are you speaking of? Just so I can keep an eye on things.

The one the bolt catch/release resides in. I haven’t heard of that problem in a long time, presumably because most people use a spacer or some quarters.

[CrowCommand]

So after a little research, Kynshot says the spacer is meant to be used with a rifle length buffer system or else you lose the function of your bolt catch.

Of course, I learn this hours after installing the carbine length tube. Maybe the a5 was the right choice for this build…..

[1168]

So after a little research, Kynshot says the spacer is meant to be used with a rifle length buffer system or else you lose the function of your bolt catch.

Of course, I learn this hours after installing the carbine length tube. Maybe the a5 was the right choice for this build…..

There are two types of 9mm spacers that make this confusing. One type is for competition “short stroke” setups that keep bolt travel to an absolute minimum for shooting PCC matches. The other type retains the functionality of the bolt catch and LRBHO, but compensates for the shorter 9mm round and lack of a cam path. The Kynshot 2.5oz spacer labeled 23278 and R15015098 is of that type.

It makes no sense that either type would behave differently when added to a rifle buffer and tube, carbine buffer and tube, or A5 buffer and tube. All have the exact same travel, thus the exact same dimensional window for a 9mm spacer.

[CrowCommand]

It makes no sense that either type would behave differently when added to a rifle buffer and tube, carbine buffer and tube, or A5 buffer and tube. All have the exact same travel, thus the exact same dimensional window for a 9mm spacer.

I believe they stated that because the standard carbine tube is 3/4” shorter than the A5/rifle tube, the spacer will eliminate the use of the bolt catch with said carbine system.

Appreciate your time explaining this, I’ve built a few 556 ARs, but this is new territory.

After sleeping on it, I will probably go with the A5 system I’ve got in the parts bin. Makes sense to me because I will be running shorter barrels/gas systems on the pistol lower; I feel like the A5 would tame any higher felt recoil from the shorter uppers.