Bravo's 16" build thread

[danm]

Dang, that's not the way a cherry poppin' range day is supposed to go... That said, I run an H2 buffer and Damaged Industries enhanced spring and have zero malfunctions...

[123wsg]

I had very similar results, I reviewed past posts and discovered that I had failed to leave the small gap between gas block and barrel step. ( thanks lrrpf52 ) After making the adjustment and truing up gas tube I was at 100 %. Darn new toys can get us boys in a rush sometimes. Of course I'm new to the modular rifle game, and almost have the second one finished ( went lw ) and hope someone will send me the detox address before I can't be saved from the addiction !!!!!!

[Jtmbtech]

I was watching a video with a very similar problem with fte it had to do with the extractor catching on the casing check it out it might be something to check https://youtu.be/kMrMUyyWV0k

[Jtmbtech]

Never mind that video the shel was being pulled out of the chamber it doesn't sound like yours is. But I would still check the extractor and spring.

[Bravo Vector Tango]

Never mind that video the shel was being pulled out of the chamber it doesn't sound like yours is. But I would still check the extractor and spring.

Yeah my train of thought right now is, it is not a magazine issue, as the only time feeding trouble occurred is when there was a piece of brass still in the chamber.

so it has to either be the ejector/extractor, or the gas system, or a combination of both.

i pulled the rail and set the gas block off of the shoulder just a hair and confirmed alignment.

I will be looking into the extractor/ejector and, as I said in an earlier post, I ordered a H buffer and a springco white spring to see if a slower unlock time puts the gas block adjustments in a more favorable spectrum.

I'll get'er running!

[Bravo Vector Tango]

Another thing to note is its experienced 2-3 "dribble out of the ejection port" ejections. Further pointing toward the working parts of the bolt.

[Jtmbtech]

If it is trying to chamber a new round the gas is pushing the bolt back so I would definitely think extractor. Unless it is slaming it open to hard.

[bob4432]

Very nice build and thanks for documenting it the way you are.

Post 32, that shows the pics of the gas journal, why is there a step so close to the port? Is there some benefit to this?

Do you feel an adjustable gas block to be necessary?

Also, adding the blue loctite to the barrel extension during assembly, is this more for the more accurate builds?

I am very new to the Grendel scene and am curious as to the "why's" of things.

Thanks in advance,
Bob

[rabiddawg]

Post 32, that shows the pics of the gas journal, why is there a step so close to the port? Is there some benefit to this?


Do you feel an adjustable gas block to be necessary?

Also, adding the blue loctite to the barrel extension during assembly, is this more for the more accurate builds

The type gas block you choose will determine if that step is used. Most front sight gas blocks mount in two locations.

Adjustable gas blocks aren't necessary but do allow you to tune the system.

I believe there is agreement among accuracy builders that seating the extension with loctite is the way to go.

[bob4432]

The type gas block you choose will determine if that step is used. Most front sight gas blocks mount in two locations.

Adjustable gas blocks aren't necessary but do allow you to tune the system.

I believe there is agreement among accuracy builders that seating the extension with loctite is the way to go.

Thx

[Bravo Vector Tango]

The type gas block you choose will determine if that step is used. Most front sight gas blocks mount in two locations.

Adjustable gas blocks aren't necessary but do allow you to tune the system.

I believe there is agreement among accuracy builders that seating the extension with loctite is the way to go.

+1

[Bravo Vector Tango]

I took her out again today, this time with some handloads of 123gr amax, over a ladder of 8208 starting at 25gr, and working up to 27.4gr.

I started the day out dialing the gas back to setting 6, I then fired 3 rounds of 25.0 grains, and 3 rounds of 25.3 grains, one round at a time loaded into the magazine, chambered and fired, to establish a baseline if functionality, all 6 of these function tests, locked the bolt back and extracted the shells about 4 feet away, toward just about 4 o'clock. Good start.

I loaded 3 rounds of 25.6 into the mag, and got a failure to extract resulting in the bolt trying to push an empty brass and a live round back into the extension.

I realized as soon as I cleared the jam that I should have grabbed my camera, and did so at that time. Then I dialed the gas down to 5, and loaded 3 rounds of 25.9 grains. Had no failures. Full function, shot about a 2moa group, neat pile of brass.

I shoot 26.2 grains with similar results, here's those 3 groups:



Soni took a break and did some breathing and mental exercises, and loaded 3 rounds of 26.5 grains, and did this: .754 group at 100 yards.



Stoked of course, I loaded 3 rounds of 26.8 grains, and this occurred:



As you can see this isn't a bolt over brass malf, just a hood old failure to extract. I cleared the jam, and had two rounds oof 26.8 left, I decided to try turning the gas down to 4, and lost functionality, resulting in the bolt not picking up the next round.

So I dialed the gas back to 6. And 3 rounds of 27.1 and 3 of 27.4 shot fine, but had similar 2moa groups to the two pictured together above from earlier in the ladder.

So I think with w favored node the gun can definitely shoot, and can also extract properly with the correct working pressure, so now I need to find a node that has both.

Also, no pressure signs at all even on the 27.4s and I would say progress is being made.

[danm]

Well at least you're making progress...

[Bravo Vector Tango]

Well at least you're making progress...

Thanks, Yeah, getting there. I need to procure some additional tooling to address the extractor, so that may delay things a tad. But as I stated in an earlier post, I do have an H buffer and a fresh spring coming, something I have noticed in other threads is most people seem to run H or H2 buffers in their Grendels, And I do believe I've seen LRRFP52 recommend at least an H. Carbine buffer+adj. gas has always gotten me there before, but perhaps in this gun, the H2 will remedy some of the extraction issues by slowing unlocking down a tad, lowering pressure and hopefully allowing the brass more time to shrink.

that is my train of thought, anyway - i will still de-horn the extractor a tad, if i can't get it going by tuning other adjustable, or variable components.

Also I just wanted to just add that i fully blame the shooter and the shooter only for those two, lousy groups , i fully believe the rifle, and the components utilized are capable of sub-MOA and do not want to do anyone a dis-service.

[Bravo Vector Tango]

Installed the LaRue RISR, as well as a sling and a few more fde pieces here and there to tie the aesthetics together.

The RISR seems really nice, and to solve the cheek weld issues, quick, repeatable eye relief that I can't screw up by pushing down with my cheek too hard.

Other than that I am still waiting on the H buffer. I still may go shoot a few rounds off today for fun.

Edit: Reporting in from the field.



I decided to take a different approach today, having more time, I prepared a prone position.

I worked up to 28gr of XBR, and she really seems to function well and shot a group that looks sub MOA with my eyes. 2ill see at home. I'm going to continue with the rest of the ladder up to 28.5gr.

I also brought a small ladder of H4895 to try.

Back to chootin'!