This is a 300BLK 24” custom green mountain barrel blank made sexiness that just because we wanted to... A2 stock, PSA lower, YHM Todd Jarrett, lots of spare other add ones... haven’t had much of a chance yet but tests are soon to come.
-
Having trouble using the site?
Contact support
300BLK 24” just because...
- Thread starter Necessary 3vil
- Start date
Well, is should be quiet suppressed anyway. It actually looks pretty good, except for one thing that doesn't fit the rest of the gun - that insert at the front of your handguard.
Presumably with that rifle configuration you're going for accuracy, so why add that non-functional piece that makes the forend not free floating? Inconsistent & partial contact between that piece and the barrel is one of the worst things you can do for accuracy.
Presumably with that rifle configuration you're going for accuracy, so why add that non-functional piece that makes the forend not free floating? Inconsistent & partial contact between that piece and the barrel is one of the worst things you can do for accuracy.
It's a YHM free float end cap. It is VERY functional. Can't quite tell if it's even making contact with the barrel. Nice stick. Load up some 110s and 125s and you should see some good velocity with the right powders.
Functional in what way? What useful purpose does it serve?
The "can't quite tell if it's making contact with the barrel" bit is the problem - if it's that close, you get contact sometimes and not others. That's bad for accuracy.
HA! I have 2 Green Mountain 22" blanks I've been meaning to finish, I just need to wait untill theres a little downtime on my millturn to finish the turning and milling in one op. I thought I was the only one that wanted a long 300 blk. Nice one Johnny!
The poster that said s\he can’t tell about the fit is not the op, and is relying on the picture.
Not designed to make contact with the barrel. Follow the link and you will see that they make one specifically for heavy barrels. And, you can see a more revealing picture on fit. Benefits besides appearance? Probably none. Affect on accuracy? Assuming no barrel contact, probably none...
https://yhm.net/forearm-end-caps-1065.html
For those who carry a firearm beyond the car to bench routine are well served by that end cap. You would be amazed to see what things in nature will make contact with the barrel and travel up into that hand guard if it was not blocked. Shooting range warriors won't run into this problem but if you're out on a hunt it could be a no-go and lead to you name a situation that complicates your day. Too bad more people don't "get out" in the field with their weapons and learn these lessons. If it's making contact with the barrel....that's a problem. No disagreement there!
Thanks and that’s only a threaded end cap for the rail to keep foreign objects out of the hand guard and makes zero contact with the barrel. It’s just a bench gun and my idea is to see just how accurate the very loved/hated 300BLK can be. Nothing but a fun project.
Interesting, and good luck.
The BO stops gaining velocity around 16" with supersonic loads, it may actually decrease velocity.
The 7.62x0 WT or the .300 Ham'r would likely be better suited to the 24" barrel.
The BO stops gaining velocity around 16" with supersonic loads, it may actually decrease velocity.
The 7.62x0 WT or the .300 Ham'r would likely be better suited to the 24" barrel.
Last edited:
I'm getting velocities well in excess of 7.62x39 territory in a 16" tube and others have tested the 110 Barnes factory load out of a 30" tube and it was still truck'in!
http://www.silverdoctors.com/wp-content/uploads/2014/10/1208801.png
Here's a great write up with another FPS chart mid-briefing showing the round through a 24" barrel.
https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2012/armaments/Wednesday13590Silvers.pdf
Last edited:
Not saying your wrong but I'd have to see that myself before I believed it. I have read that many standard velocity 22 long rifle loadings will reach their max velocity around 16-16.5". Certainly if you are handloading that wouldn't be true of all powder options in the blackout.
- common BCG
- common magazine
- light recoil
- 7.62x29 ++ energy
- .308 bullet selection (possibly the largest field)
- ideal subsonic round
- make your own brass out of .223Rem/5.56NATO cases
The rounds you mentioned are outstanding but in the AR platform it's ONLY a barrel swap and the Blackout rules the kingdom if you're shooting subs.
I own two rifles chambered in 300blk, a 6.25" SBR and a 16" Handi Rifle. They definitely have their place and purpose, but I'd have to disagree on most of your points above. I'll give you the common bolt carrier and brass, but...
Grendel and SPC mags are not exactly hard to come by
Recoil is minimal on all these calibers
The Grendel has more energy from muzzle to infinity than any 300blk load
.308 does have better bullet selection, but generally lower B.C.
A 24" barrel shooting subs is an absolute waste of quality steel
To each their own, not trying to put the project down in the slightest. It's definitely out of the norm. It just seems to me like trying to win a sprint in flip flops while a good pair of sneakers sits by the door.
Definitely going to have to experiment with some slower burning powders than would be traditionally used on this round to utilize all that extra barrel. I've exclusively used the 110gr Barnes black tips for hunting. They definitely perform well above their weight class.
Keep telling yourself that. I hunt with mine, as I think a lot of other guys here do as well, and have yet to encounter this imaginary problem of stuff being stuck inside the handguard. But if pretending those who don't use them must not hunt makes you feel good about a gimmick that's really just for looks - have at it.
And yes, I have seen them in person and know what they are and are supposedly for. They serve no actual purpose except someone thought they look cool at one point, and made up an excuse for them.
Yes I know what they are; I wasn't asking what the item is, just pointing out it doesn't fit with an otherwise well thought out rifle build.
You'd make that assumption after seeing the pic in the OP? Do you realize how much a barrel can flex relative to the handguard?
No, I’d make the assumption that pictures of items at odd angles are notorious for skewing perspective and making accurate judgement of spacing difficult. I can’t tell the spacing, but if the thickness of a dollar bill is sufficient to call a barrel freefloated, I’ll give the builder the benefit of the doubt that he can see that in RL where it may not be obvious in a pic.
This was my next question. Most .300BO builds run a pistol gas system for subsonic reliability. Did you go with a different gas system on the 24" build?
@ Yondering
I have some YHM uppers with the close out rings.
They do not touch the barrel even with presure applied.
They are dual purpose of keeping things from snagging and asteticly pleasing.
Can't see anyone having issues with one, mine have never presented a problem.
Mine have been in the mud dragged into brush and for me mostly on a square range
Without fail or degrading accuracy.
For the people that think the barrel deflects into the hand guard.
Which do you think bends first a steel barrel or an aluminum hand guard.
Stick them in a vice and try I have, barrel wins every darn time.
I have some YHM uppers with the close out rings.
They do not touch the barrel even with presure applied.
They are dual purpose of keeping things from snagging and asteticly pleasing.
Can't see anyone having issues with one, mine have never presented a problem.
Mine have been in the mud dragged into brush and for me mostly on a square range
Without fail or degrading accuracy.
For the people that think the barrel deflects into the hand guard.
Which do you think bends first a steel barrel or an aluminum hand guard.
Stick them in a vice and try I have, barrel wins every darn time.
A dollar bill is really not sufficient to call a barrel free floated unless it's a very heavy barrel and a very stiff forend. It technically is free floated at rest but that doesn't mean it won't touch sometimes, which you want to avoid for accuracy. I've seen contact marks between handguards and gas blocks that had ~3 credit card thickness of clearance; things can flex and vibrate more than you expect.
Snuby642, if you don't think barrels can deflect inside handguards, you haven't looked into it closely. It's not about whether a steel barrel or aluminum handguard "wins"; not sure what you're trying to prove there. Barrels flex, and that's easy to demonstrate for yourself. The point is to have enough clearance that it doesn't matter, and the amount of clearance needed depends on the individual parts. IMO the OP's rifle doesn't have enough clearance, based on my own experience chasing weird accuracy issues, and the solution is pretty simple. YMMV.
Carbine Length, .0110” port, and the barrel is 1-8
Just need to find time to chrono and data log everything. I’m sure subs will fly through but not really my intentions. 90gr to 155gr will likely be my loads to test.
Just need to find time to chrono and data log everything. I’m sure subs will fly through but not really my intentions. 90gr to 155gr will likely be my loads to test.
