barrel dimpling

[mtdawg169]

Ok.

I plan on installing a VLTOR A5 buffer system to help with dwell time on the 10.5 barrel.

Any suggestions to help with reliability?

Eventually it will be suppressed but I wont run it with a can all the time.

It should run pretty well with the standard A5H2 or H3. One day down the road, when you decide to suppress it, you will probably need to step up to an A5H3 or H4 and a Springco Green action spring.

No one has the Vltor kits at the moment. So if you're going to source the parts separately, you can do the following:

BCM intermediate receiver extension OR the new magpul SR25 Receiver extension (same length / both AR compatible)

Springco Green Rifle spring

Vltor A5H2 or H3

 

[Duce4trey]

That was exactly what I did.

BCM intermediate tube
Green sprinco spring
found a vltor A5 H4 buffer on gunbroker for $25.

Still looking for a H3.

I figure I will have both and see which one works best.

 

[mtdawg169]

OK, here we go...

Duce is using a Geissele gas block. The set screw spacing on the most common gas blocks is usually either 0.40 or 0.45". The BRDE jig is set up for 0.45 spacing. However, the SLR Rifleworks jigs allow for both by simply flipping the jig over and swapping the screws.

One thing to note here is that the port on the Geissele block is fairly small, so there is little room for error in terms of alignment. BCM & Vltor blocks have a significantly larger port which gives you more leeway. As a result, using a jig in this case is especially useful.

Distance from edge of block to leading edge of gas block port

Compared to the gas port on the barrel

Here, you can see the port aligns directly with the rear set screw hole.

The jig. 0.40 side facing up. The jig has two screws. One has a pointed tip, that indexes and self-centers on the gas port. The other, is a large cap head screw with a guide hole drilled right down the center.

 

[ASH556]

You'll be fine. I ran my commercial spec DD MK18 upper with 5.56 ammo and an M4-2000 90% of the time and never had an issue. I ran it with an H2 buffer and carbine spring.

Ok.

I plan on installing a VLTOR A5 buffer system to help with dwell time on the 10.5 barrel.

Any suggestions to help with reliability?

Eventually it will be suppressed but I wont run it with a can all the time.

 

[mtdawg169]

Alignment screw with jig installed on the barrel

Guide screw

Installed in the vice

I don't have three hands, so no action shots. Here's the finished product.
Totally ruined...

Perfectly aligned

And the finishing touch is using the correct set screws with an aggressive knurling on the tip

I found this turd on the floor after dropping the set screw shown above. This is an example of what NOT to use. I'm pretty sure I threw it on the floor after swapping it for a knurled tip screw a couple of months ago. It came off of a PD gun that didn't cycle. I'll give you one guess why it didn't run.

Duce's barrel in all of its engraved (and dimpled) glory!

Also interesting, here you can see that the Geissele block is compatible with a barrel pin. You can see that it would engage about half the width of the pin, which I prefer over a deeper set pin that drills completely through the barrel. Because: reasons.

 

[mtdawg169]

That was exactly what I did.

BCM intermediate tube
Green sprinco spring
found a vltor A5 H4 buffer on gunbroker for $25.

Still looking for a H3.

I figure I will have both and see which one works best.

Try it with the H4. It will probably run fine.

 

[mtdawg169]

And the second project of the evening, my new Sionics lower!

 

[Duce4trey]

mtdawg169 Very nice. Many thanks again.

 

[DADI03]

You know you could of saved a lot of people being butt hurt if you would have just let me use my drill press on it. All kidding aside, nothing better than a little piece of mind in knowing it was done right. Good luck with the rest of your build. In for pics

 

[Duce4trey]

Good luck with the rest of your build. In for pics

Thanks. I will have the upper done once I get my barrel back. Still getting some parts for the lower.

Until I get this stamp back it will have to ride on my spikes registered lower (Meaning pics will be in class III section)