Hello guys/gals

I apologize in advance if this has been covered multiple times, I googled and didn’t come up with a definitive answer.

I’m building a x39 pistol and decided to go with a 10.5 barrel possibly 11” KAK barrel if they ever come in stock again. This is going to be a range toy and trying to keep it fairly inexpensive but reliable. I have researched all the possible weak points of the x39 and already addressed them ( magazines, bolts, firing pins, extractors, etc..)

My question is will m4 feed ramps be an issue or is this a case by case issue? I will be shooting steel case RAS and don’t plan on using brass, unless I get it as cheap as steel. I have seen mixed reviews on m4 feed ramps working fine and others needed to dremel and polish the feed ramps. The KAK barrel uses m4 feed ramps I believe but BCA (I know) uses 300 blackout feed ramps. I will be mating the barrel to a standard upper receiver, so I am not sure if the feed ramps on the receiver will match up with the 300 BO barrels feed ramps.

Any advice will be helpful, I haven’t purchased the barrel yet so I’m not sure if the feed ramps will even be an issue I’m just trying to get ahead of any issues that may arise from that.

Mike

You might check out these guys for barrels:

https://www.alphashootingsports.com/105762x39CHF-p/alp105_76239nitchf.htm

Haven't shot mine yet but it is cold hammer forged and dimpled for gas blocks.   So far all of the items I've purchased from Alpha Shooting Sports has been good quality and they have been great to deal with.

We'll see about the M4 feed ramps (if the weather would improve).  

Thank you, I came across them through my searches for a barrel and didn’t know if the tin barrel extension would make a difference. Seems a better barrel than a cheap BCA or at least at appearance it does

I have an 8 1/2'' green mountain barrel in mine with M4 feed ramps and it's 100% reliable. The main issue is mags, firing pin, and trigger. and go with a heavy buffer, I run an H3 in mine. I built mine as a toy and the thing is really fun to shoot. Since I have SKS and AK47 rifles I wanted an AR-based pistol to go along with them. and because they are side charging I wanted the pistol to be side charging too. so I went with a BCA side charging stripped upper and BCG but went with a redXarms firing pin and hyperfire trigger.

KAK makes great barrels and I think you will be fine going that route if they get them back in stock. I have used several of their budget barrels over the years for builds for buddies and they have been very pleased with the accuracy.

oh and I have only shot cheap ass Tula steel case through mine because I bought a bunch before the panic at regular prices.

Awesome this is exactly what I have been looking for. I just got a 16” GMB x39 barrel and want to build a x39 pistol. From what I’ve heard some of KAK barrels are GMB blanks but idk how true that is. I picked up some asc mags and some c products mags to see which once worn along with an enhanced firing pin and x39 bolts. I just don’t want to dumb time and money into a pistol that won’t cycle and is no fun.

yeah from what I have heard that is true, they do use GMB blanks it may even say so on KAK's site if I remember right.

also, I have only used C-products mags. I bought five to start with and they all ran flawlessly so never tried any other brands.

The main issue with the ASC mags is the follower. Comparing it side by side with the C products duramag, the duramag clearly is the better functioning design. Just press the front of the follower down and you’ll see the difference. I can post some pics and of my dremel job on the asc, which helps a little with feeding.  But after loading 10 rounds in a 20 round ASC, the rounds begin to jam up and nosedive

A little late, but I have one of the KAK 11 inch value line barrels, have it in an Anderson upper receiver. I bought it new and the feed ramps had some sharp burs that would catch the bullet near the tip and prevent it from feeding the first round when hitting the bolt release.
I widened the ramp throat slightly without really changing any angles to better match the larger diameter 30 caliper round. No where near 300 black size ramps. Followed that up with a little polish, again, not a lot, just enough to take the ugly off.
This has become my favorite x39 barrel. It's not over gassed and it's not heavy. I honestly feel it's hard to beat one of these barrels when you consider the price, weight and nitride coating. Even if it needs a little clean up work.
One last thing, I run a three prong AAC flash hider and this barrel with RAS ammo does not throw fireballs. I have yet to see the first fireball in daylight.

I have a 10.5" faxon 7.62x39 that I have been shooting for night matches and also pig hunting.It was primarily built around the Tula 154 great SP ammo as last year I could buy it for $208 per M. As stated earlier with this caliber and steel case ammo for sure get the Red Star Arms longer firing pin and make sure to use full power hammer springs to avoid light strikes. The only real issues I have with mine concern extraction. Make sure to keep the chamber clean and use a good extractor. I don't think I have really had any feeding issues per session. Attached File

Mine has also run suppressed most of the time and has an adjustable gas block tuNed to the above ammo.