My 10" 300 BLK (with pics)

[snipecatcher]

10" Douglas barrel, threaded 1/2x28
Paladin machine 3 position gas-block, pistol position
YHM lightweight handguard, Spectre length
Bushmaster upper/bolt carrier, BCM/VLTOR gunfighter charging handle.
Spikes lower with Timney trigger
DPMS heavy buffer
Magpul furniture, with paperwork/wrench in storage compartment

It's been a long road. The first 1 in 8 twist barrel I got would not stabilize ANY bullets subsonic. The machinist who made me the barrel cut me a deal on the same barrel in 1 in 7 twist. It had the same issue. After some talks with Douglas barrels and Paladin machine, and the help of the people on the Quarterbore forums, it was discovered that the barrels had practically no lands left. Douglas agreed to send Paladin a stainless 1 in 7 blank. This the barrel that is currently on the rifle. It marginally stabilizes 208 A-max's, and 90 XTP's, but nothing else. It shoots supersonic loads fine.

The pistol position selectable gas-block is great. I can run pretty fast powders with lightweight subsonic bullets (or I could if they would work in my barrel) and they will cycle the action. In fact, they cycled it a bit too hard, so I added the heavy buffer. Now it cycles just about right with the silencer.

[snipecatcher]

More pics:

Gas-block


Tool I made for the gas-block


Storage for tool and paperwork

[I8asquirrel]

Very nice set up! Are you shooting the 90 gr XTP as subs?

[snipecatcher]

Very nice set up! Are you shooting the 90 gr XTP as subs?

I was, and they are very quiet, but I've decided not to shoot subs anymore in this rifle. My suppressor is in the shop right now, because something is rattling loosely inside. I think I had a baffle strike. It may have been caused by one of the 90 XTP's, as those were the only subsonics I was shooting the day that it happened. If that's the case, then my rifle really doesn't stabilize ANY bullets at subsonic velocity. It's pretty shitty that the whole purpose behind the cartridge can't be taken advantage of, but there's really nothing I can do about it at this point, I'm stuck with the barrel and won't be able to afford another one for quite some time. I'll just shoot supersonics with this barrel.
-Dan

[shuter]

Nice rig. Source please for the block contraption that holds the upper/lower together for compact carry?

Thanks

[snipecatcher]

Nice rig. Source please for the block contraption that holds the upper/lower together for compact carry?

Thanks

Large cutting board, some aluminum rod, a few other little pieces, and lots of cutting/fitting with a jigsaw and dremel. It does a good job of keeping the upper and lower from beating each other up in the bag.

I could draw up some general plans for it if you are interested in making one.

[LYNRDSKYNRD]

Great looking set up!!

[ick]

Genius. Simple yet functional. Plans would be great.

[shuter]

+1 on the plans! Very cool idea. Market it!

[ds762]

Its a shame the new barrel isn't working either.

[imyomama]

outstanding design on the holder .. please send plans !! I got to make one of those !!

[thehouseproduct]

Any load data on the 90gr XTP?

[southbreeze]

Snipecatcher,

That's as sweet a carrying device as I've seen yet! Thanks for sharing the great idea...I'll be doing something like it soon.

Hate to hear of your subsonic troubles. A Noveske upper is on the way to the house and I intended only using SS for predator control. The whole reason I went with 300 blk was because my current 7.62x39 suppressed barreled upper won't stabilize the 220grn EBR SS ammo.

What kind of range are you getting out of supersonic ammo?

Cheers,
Southbreeze

[superman007]

Glad you got it going, looks great.

How widespread is the stabilization issue? Any ideas why your having the problems? I assume the steel or rifling methods might be suspect if your having so many issues with the same blanks and provider.

Has anyone with Noveske, AAC, or Delta Company had a similar problem with stability, or wear.

[JasonAAC]

Glad you got it going, looks great.

How widespread is the stabilization issue? Any ideas why your having the problems? I assume the steel or rifling methods might be suspect if your having so many issues with the same blanks and provider.

Has anyone with Noveske, AAC, or Delta Company had a similar problem with stability, or wear.

We have not had any stability issues with factory rounds (or similarly-loaded equivalents) in our barrels.

As for wear, they are so far holding up much much better than anything in 5.56. We are working towards a life expectancy number, but Robert has placed a general expecation on our barrels of around 30,000 rounds.

[Twinsen]

Hmm, makes me doubley triple want to go with the Noveske barrel. I just gotta find a builder for this can to be.

[snipecatcher]

I really don't have anything to compare my rifle to, at least in a short barrel. The 18" 300 whisper I had before this rifle would stabilize every 30 caliber bullet I tried, including the 240 Matchkings. The barrel blank is a Douglas. It was made by Paladin Machine, who has good reviews all around. I honestly don't know what the problem is, but I've lost all faith in the ability of the 300 BLK to reliably stabilize subsonic bullets in a short barrel. I'm going to stick with 110 V-max bullets at 2150 fps from here on out. I started to draw out plans for the block that holds everything together, but got sidetracked. I'll try to get plans and some pictures up sometime, but the whole thing is really pretty simple.
Regards,
-Dan

[LYNRDSKYNRD]

I would not go foward with the assumption that short barrels will not stabilize subsonic bullets. Unfortunately it sounds like the barrel you have will not, and that sucks. I have shot only subs through my Delta Co. 9" barrel and they stabilize fine and are very accuarate to boot. Sorry you are having such a time with your set up as it is put together really nicely.

[JasonAAC]

I would not go foward with the assumption that short barrels will not stabilize subsonic bullets. Unfortunately it sounds like the barrel you have will not, and that sucks. I have shot only subs through my Delta Co. 9" barrel and they stabilize fine and are very accuarate to boot. Sorry you are having such a time with your set up as it is put together really nicely.

This is true. Factory 220's have all been fine in the AAC 9", the Noveske 8" and all of the Delta Company SBR barrels I've heard of.

[Dr.Phil]

I really don't have anything to compare my rifle to, at least in a short barrel. The 18" 300 whisper I had before this rifle would stabilize every 30 caliber bullet I tried, including the 240 Matchkings. The barrel blank is a Douglas. It was made by Paladin Machine, who has good reviews all around. I honestly don't know what the problem is, but I've lost all faith in the ability of the 300 BLK to reliably stabilize subsonic bullets in a short barrel. I'm going to stick with 110 V-max bullets at 2150 fps from here on out. I started to draw out plans for the block that holds everything together, but got sidetracked. I'll try to get plans and some pictures up sometime, but the whole thing is really pretty simple.
Regards,
-Dan

I would be pretty pissed if I were you.
This is the first I have heard of anyone having stability issues with 300 BLK / 300 Whisper(r) with subsonics rounds when using a short barrel.
As long as the twist rate is 1-8, there shouldn't be any issues.

You really should insist on a refund or replacement.

[imyomama]

delta company arms 9" barrel here too.. no problem stabilizing smk's 220.... sorry to hear about your troubles ..