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CopperSpine
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Posted: 12/18/2011 3:36:05 AM
Which one would you go with and why?

d90king
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Posted: 12/18/2011 3:44:19 AM
At this point 300BLK in SBR's with a can is hard to beat. I've been running 6.8 for a few years and like the cartridge but I think they both serve different purposes. For 12.5 and longer I like 6.8 for barrels shorter than 12.5 I will be running 300BLK.
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Posted: 12/18/2011 5:37:01 AM
Two different animals.

The mission drives the gear.

What are you going to use it for?
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Posted: 12/18/2011 7:37:07 AM
[Last Edit: 12/18/2011 7:37:07 AM by VA-gunnut]
Topic Moved
Adirondack47
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Posted: 12/18/2011 9:28:23 AM
I see that you are in NY. I asked the same question a couple of weeks ago as I planned a build for an AR I am going to use primarily for hunting. For me anyway, the biggest deciding factor was that I can use my preban magazines with the 300 AAC Blackout platform which I cant do with the 6.8. I would have to go to a proprietary magazine and of course there is no such thing as "preban" 6.8 magazines.

I think the 6.8's power factor is a bit better but there are a number of loading's available for the 300BLK that are pretty close in terms of performance and they are priced reasonably because of the availability of brass. The Barnes 110 grain TSX loading is pushing a 30 caliber bullet at 2300fps and at around $23 a box, its not a bad deal. Remington and SouthWest ammo both have FMJ ammo available for around $12 per 20 which is a little bit high for "plinkin" ammo but I would hazard a guess that 6.8 FMJ isnt any cheaper.
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Posted: 12/18/2011 9:32:25 AM
Like Mr. Cody says, two different animals. Take your pick on what your needs and wants are.

6.8 SPC - Supersonic only if you are looking to get every last bit of energy you can out of a 6.8 bullet that works well in SBR. I have a simplistict view of the 6.8 SPC SAAMI being like 223 Rem and the 6.8 SPC II being like 5.56 as far as pressures go.

300 BLK - Get decent performance for supers that will be about a 30-30 or a hair less than hot 7.62x39 loads. Works great in 20+ inch barrels down to 8" barrels. Then, screw on a can to go quiet with subsonics that will reliably cycle the action.

eracer
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Posted: 12/18/2011 9:41:05 AM
[Last Edit: 12/18/2011 9:56:05 AM by eracer]
My choice? Suppressed .300 BLK SBR. I FINALLY got the stamp for the silencer on Friday, and will be taking it to the range for some testing. I fired some subs through it without the silencer attached, and had some short-stroking issues. Shouldn't be a problem with the can attached.


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RUTGERS95
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Posted: 12/18/2011 3:29:06 PM
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'
Redtazdog
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Posted: 12/18/2011 3:39:21 PM
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.

BobRoberts
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Posted: 12/18/2011 5:01:12 PM
[Last Edit: 12/18/2011 5:01:39 PM by BobRoberts]

Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.


Plus, it will cost you more in parts, components, and ammo.
"George said "TAX? Fuck that, I THE FUCKING MAN!" Then took a bunch of shots of the whiskey he made himself and shot King George in the goddamned face." -RustedAce
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Posted: 12/18/2011 5:43:06 PM
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



...or cycle suppressed subsonic and supersonic in the same gun with no changes or adjustments whatsoever. The 6.8 is a fine round, but no, it does not "do everything you need in the 300 and more."
Altair
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Posted: 12/18/2011 6:48:03 PM
6.8:
Velocity
Energy
Range
Terminal Performance

300:
Cheaper Brass
5.56 Bolt
5.56 Magazines
Reliable and Quiet Subsonic Suppressed

Both perform well in short barrels and have good industry support. Decide which advantages are most important to you and pick one (or get both).
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Swat_dude
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Posted: 12/19/2011 1:06:51 AM
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm
BobRoberts
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Posted: 12/19/2011 1:29:29 AM
[Last Edit: 12/19/2011 1:30:20 AM by BobRoberts]

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.
"George said "TAX? Fuck that, I THE FUCKING MAN!" Then took a bunch of shots of the whiskey he made himself and shot King George in the goddamned face." -RustedAce
eracer
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Posted: 12/19/2011 8:01:06 AM

Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.

Precisely.
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Redtazdog
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Posted: 12/19/2011 8:08:46 AM
[Last Edit: 12/19/2011 8:10:10 AM by Redtazdog]
Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm


The topic is about the 6.8 vs the 300, nothing about 45 acp or a 510 whisper that will blow away all

Altair
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Posted: 12/19/2011 8:53:13 AM
Originally Posted By eracer:

Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.

Precisely.


It isn't just about BC. You can pull out the magazine of subs and put a mag of supersonics in that are much better terminal peformers than any .45ACP. The 300BLK will also run much more reliably and with standard AR mags in an AR platform. It is about versatility as well.

Also, with companies like Outlaw State Bullets coming out with good expanding subsonic bullets for the 300BLK it won't be long before that argument is completely irrelevent. They will offer similar performance and better penetration than a .45ACP bullet.
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EWP
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Posted: 12/19/2011 2:23:06 PM
[Last Edit: 12/19/2011 2:25:36 PM by EWP]
If suppressors are your thing the blk is a good choice but if you need a full power rifle cartridge then 6.8 is by far the best in the AR platform.

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Posted: 12/19/2011 2:24:25 PM
Originally Posted By Adirondack47:
I see that you are in NY. I asked the same question a couple of weeks ago as I planned a build for an AR I am going to use primarily for hunting. For me anyway, the biggest deciding factor was that I can use my preban magazines with the 300 AAC Blackout platform which I cant do with the 6.8. I would have to go to a proprietary magazine and of course there is no such thing as "preban" 6.8 magazines.

I think the 6.8's power factor is a bit better but there are a number of loading's available for the 300BLK that are pretty close in terms of performance and they are priced reasonably because of the availability of brass. The Barnes 110 grain TSX loading is pushing a 30 caliber bullet at 2300fps and at around $23 a box, its not a bad deal. Remington and SouthWest ammo both have FMJ ammo available for around $12 per 20 which is a little bit high for "plinkin" ammo but I would hazard a guess that 6.8 FMJ isnt any cheaper.


Tula will be releasing cheap steel cased 6.8 ammo next year.

From a post on 68forums:

email from the President of Tulammo USA:

We are working on the 6.8 cartridge for 2012. I cannot give you a specific date, but we will have the cartridge available sometime next year. We should be able to provide a less costly version than anything on the market at this time.
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Posted: 12/19/2011 2:47:38 PM
[Last Edit: 12/19/2011 2:48:10 PM by Swat_dude]
Originally Posted By Altair:
Originally Posted By eracer:

Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.

Precisely.


It isn't just about BC. You can pull out the magazine of subs and put a mag of supersonics in that are much better terminal peformers than any .45ACP. The 300BLK will also run much more reliably and with standard AR mags in an AR platform. It is about versatility as well.

Also, with companies like Outlaw State Bullets coming out with good expanding subsonic bullets for the 300BLK it won't be long before that argument is completely irrelevent. They will offer similar performance and better penetration than a .45ACP bullet.


You are missing my point. Anytime the conversation comes up about 300 blk vs. 6.8, the 300blk fan boys always point to its suppressor capability. My point is the loading for subsonic suppressed 300blk is less than ideal. So trying to argue the 300blk is superior over 6.8 because of its subsonic ability is just plain silly.

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Posted: 12/19/2011 2:53:50 PM
[Last Edit: 12/19/2011 2:56:43 PM by Swat_dude]
Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.


The HST with 1000 fps at the muzzle will still be traveling 913 fps at 100 yards so someone with a BC calculator can calculate. The HST will still realiably expand down to 700 fps. Again, what is the velocity of the 220 grain out of a 7.5 inch barrel??? The 1010 is for the 16 inch barrel. I am convinced the .45 HST +P would dominate it in performance out to 200 yards.

Why would you choose a rifle to shoot subsonic ammo that can't even best a handgun round? I would take the 6.8 moving an 85 grain bullet at 2400 fps out of a 7.5 inch barrel and just live with the sonic boom.
eracer
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Posted: 12/19/2011 2:55:41 PM
[Last Edit: 12/19/2011 2:55:55 PM by eracer]

Originally Posted By Altair:
Originally Posted By eracer:

Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.

Precisely.


It isn't just about BC. You can pull out the magazine of subs and put a mag of supersonics in that are much better terminal peformers than any .45ACP. The 300BLK will also run much more reliably and with standard AR mags in an AR platform. It is about versatility as well.

Also, with companies like Outlaw State Bullets coming out with good expanding subsonic bullets for the 300BLK it won't be long before that argument is completely irrelevent. They will offer similar performance and better penetration than a .45ACP bullet.

I almost asked whether the .45 HK UMP has a supersonic option.

I was not aware of the Outlaw State info. Thanks for that!

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Posted: 12/19/2011 3:11:45 PM
Originally Posted By eracer:

Originally Posted By Altair:
Originally Posted By eracer:

Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.

Precisely.


It isn't just about BC. You can pull out the magazine of subs and put a mag of supersonics in that are much better terminal peformers than any .45ACP. The 300BLK will also run much more reliably and with standard AR mags in an AR platform. It is about versatility as well.

Also, with companies like Outlaw State Bullets coming out with good expanding subsonic bullets for the 300BLK it won't be long before that argument is completely irrelevent. They will offer similar performance and better penetration than a .45ACP bullet.

I almost asked whether the .45 HK UMP has a supersonic option.

I was not aware of the Outlaw State info. Thanks for that!



Outlaw State bullets
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Posted: 12/19/2011 3:33:32 PM
Originally Posted By CopperSpine:
Which one would you go with and why?



Depends on what you want to do.

If I was looking for quiet operation and/or limiting myself to CQB->100y I'd take the .300 as it's got good subsonic loads.

If I wanted a rig for hunting - hands down the 6.8 for better hunting loads (and a wider selection) as well as expanding at much longer ranges (and less drift & drop).

For a general-purpoe tactical rifle? Again I'd take the 6.8 for the range aspect (minimal drop to 300M) - drop at 500y similar to 7.62x51NATO M80 and 75gr OTM 5.56.

If you're looking for a plinking rifle the .300 will have cheaper ammo and be cheaper to reload for.

Looking for a SBR? It's a tossup as they both work very well from SBRs.

They are both good cartridges, but have different strengths.
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eracer
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Posted: 12/19/2011 3:49:44 PM
[Last Edit: 12/19/2011 3:52:25 PM by eracer]

Originally Posted By Swat_dude:
Originally Posted By BobRoberts:

Originally Posted By Swat_dude:
Originally Posted By Redtazdog:
Originally Posted By RUTGERS95:
my question would be, 'why a 300blk when the 6.8 will do everything you need in the 300 and more'

The 6.8 will not be even close in quiet with a can.



Why the 300blk for a suppressed SBR? A .45 HK UMP firing 230 gr HST +P's will give way better terminal performance than the 300 blk 220 grn Remmington loading, which is the "quiet" subsonic round you refer to. For that matter, why not use a Glock 21 with a Kreiss 30 round mag and suppressor? The subsonic 300 blk is an answer looking for a question.

Remmington 220 grain: 1010 fps out of 16-inch barrel!!! Keep in mind this is a rifle bullet designed for rifle velocities, not handgun velocities.

Federal HST .45 230 gr +P fired from 6-inch barrel: 1010 fps. This is a handgun round and typically expands to almost an inch at the handgun velocities it was designed to fire at.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/DocGKRData/45_CorbonDPX.htm

What is the BC of .45 pistol bullets? The 308 bullets will retain much more energy and will bleed of velocity much more slowly, thus they will have a greater range then 9mm or 45 acp.


The HST with 1000 fps at the muzzle will still be traveling 913 fps at 100 yards so someone with a BC calculator can calculate. The HST will still realiably expand down to 700 fps. Again, what is the velocity of the 220 grain out of a 7.5 inch barrel??? The 1010 is for the 16 inch barrel. I am convinced the .45 HST +P would dominate it in performance out to 200 yards.

Why would you choose a rifle to shoot subsonic ammo that can't even best a handgun round? I would take the 6.8 moving an 85 grain bullet at 2400 fps out of a 7.5 inch barrel and just live with the sonic boom.

The 220gr. .308 bullet in the .300 BLK starts with more energy than the .45 HST, and because of its higher BC, ends up with more energy at 100 yards.

As for your second question, once subsonic .308 bullets are developed that can reliable fragment at 1000 fps are developed, a suppressed .300 BLK is a fine home defense weapon. The 6.8? Not so much. Would I pick the .300 BLK over the 6.8 for 0-400 yards outdoors? Nope. I'd pick the 6.5 Grendel. But that's another discussion altogether.

You could try driving the moisture out in an oven on a very low heat setting, but you might just burn your house down instead. - RyJones
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Posted: 12/19/2011 5:08:05 PM
[Last Edit: 12/19/2011 5:08:44 PM by CopperSpine]
Thanks for all the info guys,

I am looking to go with a suppressed sbr.

I have other toys for >100yds

I am building my first AR and didn't want to go .223

Any tips on uppers? I found some complete uppers or just the barrel for 300blk, what should I look for in a barrel?
Any brands you would shy away from?

I am doing this on a quasi budget. So a $1000+ upper is out of the question unless you can convince me otherwise.

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