10.2" 300 BLK build - questions about SLR gas block-

[Jonny4523]

Here's a build we just completed last night. Spec's are as follow:

- BCM M4 Upper
- Noveske 10.2" barrel
- Noveske matched bolt
- LMT Enhanced Carrier
- SLR adjustable gas block
- BCM 9" KMR

Just a few notes: I had a lot of issues with the SLR on the pistol length gas system. When I was first putting it together, I put the carrier in the upper as a gas-tube alignment test as I always do. But for the first time ever, I had a HARD stop with the gas key hitting the gas tube. Not even close to mating using DD carrier. Tried another carrier and a few more gas tubes (including one supplied by SLR). All hard stop. I'm an engineer and have access to several CMMs. So I decided to measure the gas block bore centerline to gas tube centerline distance. Quite a bit of a difference between the SLR and the other two I measured (Noveske and BCM). I measured a .093" difference. We emailed SLR about this and their response was pretty much "Others have used it just fine". They offered a full refund, but we still wanted to use it for its functionality in a suppressed SBR. So my buddy designed and made an alignment jig he used to change the offset in the bend of the gas tube. It worked beautifully.

In testing, the gas block functioned very well. We only put a half mag of subsonics through last night while adjusting it, but adjustment points were well defined and compared to my 5.56 SBR, I was very pleased to see zero gas in the face while shooting suppressed.

Has anyone else experienced similar issues with the SLR, or any other adjustable gas block for that matter? Without the jig we made for the gas tube, this would not have been a functional build.

Also, we picked the BCM M4 upper for the tight barrel extension ID. The fit between the upper and the barrel was so tight, we froze the barrel, heated the upper, and still had a slight tap fit.

[Slvr Surfr]

Nice boom stick and Saker!

It is common to fine tune the gas tube to match the carrier key on new builds. Most of my builds have required minor tweaks within the chamber area. Any gross adjustments can be done from the gas block side.