Few questions. About 300blk build

[toolboxluis00200]

OK guy I have afew questions
What adjustable gas block are some of you guys are using??
What is your favored ammo that you can buy of the shelf sonic and subsonic ammo ??
Is the BCG the same as a 556 correct??

Any suggestions are welcome


ok small update UV is not sending me the 16 barrel instead a 10.5
so now i need a new rail ?? i am looking at some 10inch rails and some .30cal muzzle breaks all so

[alamo5000]

I just bought an SLR Sentry 7 gas block from SLR Rifleworks. I like it so far but I am sure there are a number of options. I did the T&E on the upper that had a Syriac gas block...that one functioned about the same as the SLR one. I think either would be a good choice, not because I am an expert but because they both supposedly come from reputable companies and based on what I have seen, both are extremely solid and easy to use. Plus you can really fine tune your rifle when you have 15 or so settings to choose from... It's not like an A setting a B setting or a C setting...

Truth be told I am still learning about mine but I looked into them before I bought and they (and I am sure several other options) would be good choices.

The BCG is the same. The brass is 5.56 brass that is chopped off and resized length wise.

EDIT: and FWIW I think you will pay out the nose for decent off the shelf .300 BO ammo. If you plan on shooting it a lot I highly recommend getting into reloading.

[Mecha_Arms]

I really like the Barnes VOR-TX supersonic ammo. As mentioned, it's expensive. Reloading is definitely recommended with 300 BLK.

I haven't used it, but Gemtech has a sale right now on subsonic ammo.

[toolboxluis00200]

I just bought an SLR Sentry 7 gas block from SLR Rifleworks. I like it so far but I am sure there are a number of options. I did the T&E on the upper that had a Syriac gas block...that one functioned about the same as the SLR one. I think either would be a good choice, not because I am an expert but because they both supposedly come from reputable companies and based on what I have seen, both are extremely solid and easy to use. Plus you can really fine tune your rifle when you have 15 or so settings to choose from... It's not like an A setting a B setting or a C setting...

Truth be told I am still learning about mine but I looked into them before I bought and they (and I am sure several other options) would be good choices.

The BCG is the same. The brass is 5.56 brass that is chopped off and resized length wise.

EDIT: and FWIW I think you will pay out the nose for decent off the shelf .300 BO ammo. If you plan on shooting it a lot I highly recommend getting into reloading.

i mite go whit the SLR gas block plus ther local to me i can just drive up and get on
i did not remember if the BCG was the same as the 556 thanks for the reminder :)
yeah this will be more of a HD upper so i will not shoot it a lot maybe one day if i have the space and the money i can look at reloading the 300blk ammo

[toolboxluis00200]

I really like the Barnes VOR-TX supersonic ammo. As mentioned, it's expensive. Reloading is definitely recommended with 300 BLK.

I haven't used it, but Gemtech has a sale right now on subsonic ammo.

cool i will look into that company the Gemtech dose have some nice 220GR sub sonic ammo

[alamo5000]

i mite go whit the SLR gas block plus ther local to me i can just drive up and get on
i did not remember if the BCG was the same as the 556 thanks for the reminder :)
yeah this will be more of a HD upper so i will not shoot it a lot maybe one day if i have the space and the money i can look at reloading the 300blk ammo

They have several styles and types so look on their website. Some are clamp on. Others are set screw. Mine is the set screw type. You'll have to ask someone with more technical knowledge than me as to what kind is better or why one over the other....all I know is I try my best to not buy junk and I most certainly haven't been disappointed with hardly anything ever recommended to me here on WEVO.

It's just me but I would rather save up and get something I know I will enjoy and that will work. I am probably not your guy that would try to build a $500 AR... so keep that in mind LOL... not that I am made out of money, but I would rather wait and get something I know I will enjoy and that will give me no problems.

[bzdog]

Personally, I'd just go with pistol gas, an H2 buffer and not worry about an adjustable gas block, but.. *shrug*.

WRT defensive ammunition, there are only a couple I'd consider.

Personally, I keep a stock of the Barnes black tips for defense. These should maintain rifle velocities even in an SBRs to ~200 yards and will still expand much farther than that. They are barrier blind as well. The only downside is they may penetrate a bit more than is optimal in certain applications.

As an alternative to the Barnes black tips, the 78gr Lehigh is interesting. Super fast, fragmenting. Should provide a similar effect to fragmenting 5.56, but bigger. Should be better if you need to minimize penetration.

The think to keep in mind is many bullets designed for .308 Win don't perform optimally in 300 BLK applications. There are a fair number of them that do "OK" and some that don't work well at all for one reason or another, but for optimal performance, you need something designed for 300 BLK, and optimally, something light.

Because of the large projectile, it's easy to end up with something that is heavier and slower, and when you dip too far below 2000fps, you potentially lose the rifle wound characteristics. So even with supers, you typically want to stick to something on the light end of the spectrum, say < 131gr.

Personally I prefer supersonic over subsonic for defense since you drop from rifle wound characteristics with supers, down to pistol wound characteristics with subs. There are a fair number of subs for 300 BLK, but AFAIK there are only one or two that actually expand. Non expanding subs would drop you even further in performance, down to something like .45 BALL wound profiles.

The other thing to look out for is certain sub loads have issues feeding in AR mags or cycling correctly.

So for me, if I were to consider subs, pretty much the only thing I'd go for is the Lehigh 168gr as it both feeds well in an AR and fractures.

There are a couple of high quality training rounds from larger companies. There are a LOT of small companies making training quality ammunition with .308 Win bullets. Quality varies, I'm disinclined to try to sift through them to find something decent at enough of a discount to make the effort worth while. YMMV.

-john


SUPERSONIC

Barnes black tip
barrier blind, expanding, rifle velocities (older version 110gr, newer version 120gr)
http://www.midwayusa.com/product/430...free-box-of-20
http://www.midwayusa.com/product/551...free-box-of-20

Lehigh Defense 78gr whisper CQD
light, fast
http://www.lehighdefense.com/product...lead-free-ammo

SUBSONIC

Lehigh Defense 168gr Controlled Fracturing (SKU 02301168L)
http://www.lehighdefense.com/collect...per-168gr-ammo
http://www.300blktalk.com/forum/view...92406&start=10 (see post by "Dr. Phil")

( Fracturing, designed to feed in AR )

TRAINING

Remington UMC 120gr (L300AAC1)
http://www.sgammo.com/product/reming...gton-umc-ammo-

Barnes RangeAR
http://www.midwayusa.com/product/977...ProductFinding

[toolboxluis00200]

They have several styles and types so look on their website. Some are clamp on. Others are set screw. Mine is the set screw type. You'll have to ask someone with more technical knowledge than me as to what kind is better or why one over the other....all I know is I try my best to not buy junk and I most certainly haven't been disappointed with hardly anything ever recommended to me here on WEVO.

It's just me but I would rather save up and get something I know I will enjoy and that will work. I am probably not your guy that would try to build a $500 AR... so keep that in mind LOL... not that I am made out of money, but I would rather wait and get something I know I will enjoy and that will give me no problems.

Thanks for the info. I like the set screew one my self they fill more stable to me any way plus I did the numbers. It won't be a $500 rifle lol

[toolboxluis00200]

Personally, I'd just go with pistol gas, an H2 buffer and not worry about an adjustable gas block, but.. *shrug*.

WRT defensive ammunition, there are only a couple I'd consider.

Personally, I keep a stock of the Barnes black tips for defense. These should maintain rifle velocities even in an SBRs to ~200 yards and will still expand much farther than that. They are barrier blind as well. The only downside is they may penetrate a bit more than is optimal in certain applications.

As an alternative to the Barnes black tips, the 78gr Lehigh is interesting. Super fast, fragmenting. Should provide a similar effect to fragmenting 5.56, but bigger. Should be better if you need to minimize penetration.

The think to keep in mind is many bullets designed for .308 Win don't perform optimally in 300 BLK applications. There are a fair number of them that do "OK" and some that don't work well at all for one reason or another, but for optimal performance, you need something designed for 300 BLK, and optimally, something light.

Because of the large projectile, it's easy to end up with something that is heavier and slower, and when you dip too far below 2000fps, you potentially lose the rifle wound characteristics. So even with supers, you typically want to stick to something on the light end of the spectrum, say < 131gr.

Personally I prefer supersonic over subsonic for defense since you drop from rifle wound characteristics with supers, down to pistol wound characteristics with subs. There are a fair number of subs for 300 BLK, but AFAIK there are only one or two that actually expand. Non expanding subs would drop you even further in performance, down to something like .45 BALL wound profiles.

The other thing to look out for is certain sub loads have issues feeding in AR mags or cycling correctly.

So for me, if I were to consider subs, pretty much the only thing I'd go for is the Lehigh 168gr as it both feeds well in an AR and fractures.

There are a couple of high quality training rounds from larger companies. There are a LOT of small companies making training quality ammunition with .308 Win bullets. Quality varies, I'm disinclined to try to sift through them to find something decent at enough of a discount to make the effort worth while. YMMV.

-john


SUPERSONIC

Barnes black tip
barrier blind, expanding, rifle velocities (older version 110gr, newer version 120gr)
http://www.midwayusa.com/product/430...free-box-of-20
http://www.midwayusa.com/product/551...free-box-of-20

Lehigh Defense 78gr whisper CQD
light, fast
http://www.lehighdefense.com/product...lead-free-ammo

SUBSONIC

Lehigh Defense 168gr Controlled Fracturing (SKU 02301168L)
http://www.lehighdefense.com/collect...per-168gr-ammo
http://www.300blktalk.com/forum/view...92406&start=10 (see post by "Dr. Phil")

( Fracturing, designed to feed in AR )

TRAINING

Remington UMC 120gr (L300AAC1)
http://www.sgammo.com/product/reming...gton-umc-ammo-

Barnes RangeAR
http://www.midwayusa.com/product/977...ProductFinding

Thank you for the info and links. I will all so look in to good mags for the 300blk

[BC98]

I would skip the adjustable gas block and pick up a barrel from a known-good maker that will function correctly. Noveske, AAC, and Ballistic Advantage all have solid offerings.

Above, someone had mentioned the 120gr OTFB ammo (L300AAC1) for training ammo. Be aware that Remington has discontinued that load for the L300AAC2, which is more expensive. The case and bullet are both produced by Barnes and it's selling for around $19 per box.

If the link for the 120gr ammo is good, pick it up. Accuracy for me was okay (not stellar) and it functioned 100%. I would definitely look into reloading. I've had good accuracy with 125gr Speer TNT's, which are also inexpensive, and converted brass.

There's no real limitation on mags. You can use any standard USGI mag for 300 BLK. You do have to watch OAL if you start to reload your own ammo as the bullet diameter can interfere with the the front stiffening rib in the mag.

[bzdog]

Thank you for the info and links. I will all so look in to good mags for the 300blk

Just get good mags. If you have problems, it's probably the ammunition.

I use M3 windowed PMags and GI, but any quality mag should be fine.

-john

[SINNER]

He was given a Rainier Ultramatch carbine length barrel. And I have 5 different Blackouts in various lengths and gas systems and would never build another one again that I planned on subs and supers without a adjustable gas block.

[SINNER]

Blackouts feed better than 5.56 rounds in every mag I have used. From cheap USGI copies to Hexmags and Lancers. The minimal shoulders feed flawlessly.

[bzdog]

What gas and buffer? Pistol gas and H2 should be OK with supers or subs + suppressor.

IIRC, may not lock bolt on last round with subs and NO suppressor.

-john

[bzdog]

Accuracy for me was okay (not stellar) and it functioned 100%.

Yes, the UMC is reliable and has high quality brass (if you wish to reload), but BC98's accuracy observations are echoed on the net.

Actually I've seen similar claims for the pre-loaded Barnes ammunition, although the black tip bullet is available for reloaders if more precision is needed.

-john