Modern Sporter builds Q&A

Tried my MS today. It’s having issues with feeding and not locking bolt to rear. The tolerance seems pretty tight on the bolt catch where it meets the face of the bolt. Some mags choked on every round or 2nd round. As it got broke in seems to run better. Went 3 full mags with not issue. Then having intermittent issues. My question is obviously I’ll chwck gas block alignment bc it seems undergassed. But I’m running a normal adjustable stock with carbine buffer spring and weight. Could this also be causing? Should i switch to rifle length spring and weight ? I’m

any luck fixing this?
 
I really don't know why people don't just buy adjustable gas blocks when building their rifles.

You would never have these problems to begin with.





Tried my MS today. It’s having issues with feeding and not locking bolt to rear. The tolerance seems pretty tight on the bolt catch where it meets the face of the bolt. Some mags choked on every round or 2nd round. As it got broke in seems to run better. Went 3 full mags with not issue. Then having intermittent issues. My question is obviously I’ll chwck gas block alignment bc it seems undergassed. But I’m running a normal adjustable stock with carbine buffer spring and weight. Could this also be causing? Should i switch to rifle length spring and weight ? I’m
 
I really don't know why people don't just buy adjustable gas blocks when building their rifles.

You would never have these problems to begin with.
Well actually all an adjustable gas block dose is reduce gas soo if you’re under gassed it’s not gonna help, I have an adjustable gas block and low mass carrier and I’m running just about full open to the point I should have just got a normal gas block, I’m guessing it would be more useful on a shorter gas system. Also I had similar issues with my bolt not locking back it ended up being my captured buffer system. For what ever reason it won’t let my bolt travel far enough to lock open. I have not tried it in my AR to see if it’s the buffer or the MS, I even tried spinning out my buffer tube a couple turns. I put a regular buffer in my MS and it works great
 
Well actually all an adjustable gas block dose is reduce gas soo if you’re under gassed it’s not gonna help, I have an adjustable gas block and low mass carrier and I’m running just about full open to the point I should have just got a normal gas block, I’m guessing it would be more useful on a shorter gas system. Also I had similar issues with my bolt not locking back it ended up being my captured buffer system. For what ever reason it won’t let my bolt travel far enough to lock open. I have not tried it in my AR to see if it’s the buffer or the MS, I even tried spinning out my buffer tube a couple turns. I put a regular buffer in my MS and it works great

^^this

A rifle length gas system is not suited for an adjustable gas block and should be properly timed by utilizing the correct buffer weight, proper spring length and tension, proper buffer tube lengths (yes commercial and mil-spec are different - even one mil-spec to another can be different) and last but not least the correct bolt carrier group. These are the items that should be experimented with.

Leave the adjustable gas blocks to the pistol-some Carbine and suppressed builds.
 
Depends on what you are doing and the components you are using. But yes an adjustable gas block is only to reduce gas not increase.

In my eyes it is better to correct the problem at the source.
Not enough gas, check the port size, gas block alignment, gas block itself for obstructions, then double check the other components and ensure you are using standard parts and not a heavy buffer or heavy spring.
Too much gas and I like to start at the source of the problem. But since you can't make the port smaller I like an adjustable gas block as opposed to band aid solutions like heavier buffers and springs.

I have my rifle length gas dialed back a bit, but I am also using a low mass BCG, Taccom buffers and spring that are both lighter than standard. I think its retarded to use a heavy buffer with a low mass BCG, defeats the purpose.
But my intention is likely different from others.
 
Last edited:
I really don't know why people don't just buy adjustable gas blocks when building their rifles.

You would never have these problems to begin with.

Adjustable gas block wouldn’t have helped. My buffer tube seems to be out of spec not allowing bcg to travel far enough to the rear causing a short stroke type failure. New buffer tube on order.
 
Depends on what you are doing and the components you are using. But yes an adjustable gas block is only to reduce gas not increase.

In my eyes it is better to correct the problem at the source.
Not enough gas, check the port size, gas block alignment, gas block itself for obstructions, then double check the other components and ensure you are using standard parts and not a heavy buffer or heavy spring.
Too much gas and I like to start at the source of the problem. But since you can't make the port smaller I like an adjustable gas block as opposed to band aid solutions like heavier buffers and springs.

I have my rifle length gas dialed back a bit, but I am also using a low mass BCG, Taccom buffers and spring that are both lighter than standard. I think its retarded to use a heavy buffer with a low mass BCG, defeats the purpose.
But my intention is likely different from others.

You bring up a good point with the low mass BCG because it does defeat the purpose if one is used with a heavier buffer to compensate. My feeling is that these specialty shops and manufacturers all promote these pieces for sales over purpose. I know we like spending on toys which is fine but are they really needed? I am not criticizing as I even have one to try because I am like a Crow with shiny things.
 
Adjustable gas block wouldn’t have helped. My buffer tube seems to be out of spec not allowing bcg to travel far enough to the rear causing a short stroke type failure. New buffer tube on order.
how do you know it’s out of spec? Did you check the spring because you would hate to change the tube and have the identical issue when using the original spring.
 
Anyone have issues with gen3 pmags?

Yes, I have had issues with gen 3 pmags not locking in at all. They have a chunk of plastic on the back side that seems to hit the bottom of the magwell. Gen 2 pmags i could get them in fine but they wont drop free. I couldn't get my Tapco mags to lock in either as they were catching a little lip of the upper where the upper and lower meet. Also IMI 10 rounders are pretty tight. the old ATRS mags fit great. I haven't tried any steels mags but sounds like they work fine for most guys so I have some coming.

I think someone was going to send ATRS some magazines to test. Not sure where they will go from there.
 
Yes, I have had issues with gen 3 pmags not locking in at all. They have a chunk of plastic on the back side that seems to hit the bottom of the magwell. Gen 2 pmags i could get them in fine but they wont drop free. I couldn't get my Tapco mags to lock in either as they were catching a little lip of the upper where the upper and lower meet. Also IMI 10 rounders are pretty tight. the old ATRS mags fit great. I haven't tried any steels mags but sounds like they work fine for most guys so I have some coming.

I think someone was going to send ATRS some magazines to test. Not sure where they will go from there.

My metal mags work fine.

 
how do you know it’s out of spec? Did you check the spring because you would hate to change the tube and have the identical issue when using the original spring.


Yes. ID of the tube is shorter than my colt.
 
how do you know it’s out of spec? Did you check the spring because you would hate to change the tube and have the identical issue when using the original spring.

I had a buffer tube with a step in the end of it. Almost like it wasnt done being machined. Caused me problems. Short strokes and couldn't use a scs in it and the thread were out of spec and wouldnt screw into my ms. It went in the garbage.
 
I got Triggertech adaptable to fit by removing the adjustment screw and removing material from the back of the pack. I am leaving the screw out since current trigger pull is sitting at 2.1lbs but could run it with the adjustment screw in as well if you wanted.

Couple things left to do on my build since the superlative adjustable touches the handguard so looking for a different .936 adjustable (anyone have any leads on this? I’ve tried the usual suspects) and my current bolt/barrel combo failed headspace on the no-go and I don’t have a field gauge.
 
I got Triggertech adaptable to fit by removing the adjustment screw and removing material from the back of the pack. I am leaving the screw out since current trigger pull is sitting at 2.1lbs but could run it with the adjustment screw in as well if you wanted.

Couple things left to do on my build since the superlative adjustable touches the handguard so looking for a different .936 adjustable (anyone have any leads on this? I’ve tried the usual suspects) and my current bolt/barrel combo failed headspace on the no-go and I don’t have a field gauge.

Do you have a picture showing how much you needed to remove from the back of the trigger?
 
I can’t post pictures but basically almost level with the rest of the pack, and then made a 45ish degree angle down on the back, you can see what material needs to go when looking at it
 
I got Triggertech adaptable to fit by removing the adjustment screw and removing material from the back of the pack. I am leaving the screw out since current trigger pull is sitting at 2.1lbs but could run it with the adjustment screw in as well if you wanted.

Couple things left to do on my build since the superlative adjustable touches the handguard so looking for a different .936 adjustable (anyone have any leads on this? I’ve tried the usual suspects) and my current bolt/barrel combo failed headspace on the no-go and I don’t have a field gauge.

Do you have a picture showing how much you needed to remove from the back of the trigger?

I've been emailing back and forth with Triggertech regarding this, and they've stated that the back of the housing can be machined/cut but you'd need a new (shorter) set screw in there.

With their newest release hanging just around the corner, and it looks to be an absolutely incredible trigger, I really want to make sure we have something figured out for a simple straight-forward solution for the compatibility with their larger trigger housings.
 
Back
Top Bottom