Need 300 whisper load help!
You are Unregistered, please register to use all of the features of FirearmsTalk.com!    

Firearm & Gun Forum - FireArmsTalk.com > Gear & Accessories > Ammunition & Reloading >

Need 300 whisper load help!


Reply
 
LinkBack Thread Tools Display Modes
Old 07-28-2015, 03:23 AM   #1
Feedback Score: 0 reviews
 
Wallace's Avatar
 
Join Date: Feb 2015
Posts: 198
Liked 50 Times on 36 Posts

Default Need 300 whisper load help!

So I was just outside shooting some loads for my 300 blackout/whisper that I have made. I am shooting a Smith&Wesson M&P 15 suppressed. I have loaded different loads using 208 grain Hornady A-Max bullets with both Hodgdon lil gun and Winchester 296 powders with velocities from 1000 fps to 1148 fps. I'm also using cci small rifle primers. I'm trying to keep it subsonic and I really like the 208 grain A-Max bullets so I would like to keep those. My problem is the loads aren't cycling through my action. I tried the lil gun powder first and no success with different powder charges. Same goes for the Winchester 296 powder. My question is it the gas system? The buffer? The powder? I have no idea. If anyone knows the answer to my problem I would greatly appreciate the knowledge.


Wallace is offline  
 
Reply With Quote

Join FirearmsTalk.com Today - It's Free!

Are you a firearms enthusiast? Then we hope you will join the community. You will gain access to post, create threads, private message, upload images, join groups and more.

Firearms Talk is owned and operated by fellow firearms enthusiasts. We strive to offer a non-commercial community to learn and share information.

Join FirearmsTalk.com Today! - Click Here


Old 07-28-2015, 11:51 AM   #2
Moderator
FTF_MODERATOR.png
Feedback Score: 1 reviews
 
robocop10mm's Avatar
 
Join Date: Jul 2007
Location: Austin,Texas, by God!!
Posts: 11,319
Liked 4003 Times on 2057 Posts
Likes Given: 493

Default

"Not cycling" is a little generic. Is it "short stroking"? Are you testing with the suppressor on or off. The suppressor will retain pressure in the gun longer. A load that works fine with the suppressor may cause problems unsupressed.

A little more on the set up may help. Gas system length? Buffer weight?

If it is short stroking with the suppressor in place, you are severely under gassed with that load. Up the load (within reasonable limits) until you get proper cycling. Do not concern yourself with "book" velocity. You need to Chrono the load to insure you are still subsonic.

Check the gas key. Is it tight? You can get gas bleed from a loose gas key that will adversely affect cycling. Remove the handguard and check for gas bleed at the front of the gas tube. Black buildup on the outside of the tube is a good indicator. Replace the tube if leaking.

Look at a different powder if you cannot get it to work. Suppressed, subsonic .300 Blk is a new (ish) proposition. Some degree of experimentation is necessary to get it right in a given gun


__________________
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball
robocop10mm is offline  
 
Reply With Quote
Old 07-28-2015, 12:16 PM   #3
Feedback Score: 0 reviews
 
Wallace's Avatar
 
Join Date: Feb 2015
Posts: 198
Liked 50 Times on 36 Posts

Default

Yes sir it is short stroking with the suppressor on. I have upped my powder charge to the very maximum it can go and still be subsonic. I don't know much about the set up of the Smith & Wesson M&P 15 300 blackout but it's only had maybe 100 rounds through it so it's still fairly new. Nothing internal on the gun has been changed the only thing I have added to it is the stock and a rail. I can take the gun apart and clean it and fire it, I would say I'm still a newbie to the AR platform so unfortunately that's all the information on the setup I know.
Wallace is offline  
 
Reply With Quote
Old 07-28-2015, 01:17 PM   #4
FTF_SUPPORTER.png
Feedback Score: 0 reviews
 
Join Date: Mar 2013
Posts: 3,033
Liked 2489 Times on 1378 Posts
Likes Given: 1308

Default

Quote:
Smith & Wesson M&P 15 300 blackout
This has a "carbine" length gas system, yes?

Even with a suppressor I doubt you will get this AR to cycle reliably with weak charges of fast Pistol powders.

Semi-autos operate off the amount of gas generated when the powder is burned.

The faster the powder burn rate, the less gas produced.

No gas, no cycle.

I would switch to a slower burning powder, maybe 1680 and see if you can get your Subs to cycle.

http://www.accuratepowder.com/wp-content/uploads/2010/09/WP_LoadSpec_1-23-14.pdf
__________________
Legislation: During the Romney Administration, no anti-Second Amendment or anti-sportsmen legislation made its way to the Governorís desk.

http://www.goal.org/newspages/romney.html
mseric is offline  
locutus Likes This 
Reply With Quote
Old 07-28-2015, 01:18 PM   #5
Moderator
FTF_MODERATOR.png
Feedback Score: 1 reviews
 
robocop10mm's Avatar
 
Join Date: Jul 2007
Location: Austin,Texas, by God!!
Posts: 11,319
Liked 4003 Times on 2057 Posts
Likes Given: 493

Default

Some research indicates folks are getting better results for AA 1680 instead of the W-296/H110 with the subsonic loads
__________________
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball
robocop10mm is offline  
 
Reply With Quote
Old 07-28-2015, 01:40 PM   #6
Feedback Score: 0 reviews
 
Wallace's Avatar
 
Join Date: Feb 2015
Posts: 198
Liked 50 Times on 36 Posts

Default

Thanks guys. I will keep the W296 and the H lil gun for my supersonic loads.
Wallace is offline  
 
Reply With Quote
Old 07-28-2015, 09:19 PM   #7
Feedback Score: 0 reviews
 
oO_Rogue_Oo's Avatar
 
Join Date: Feb 2014
Location: Central MS
Posts: 350
Liked 160 Times on 123 Posts
Likes Given: 16

Default

Lil'gun actually does well for subs and is one of the powders I've had success with. IMR4227 is the powder I've worked with most developing my sub loads though because lil'gun and 1680 was unavailable for so long I had no choice. 296/H110 need to be relegated to supersonic only. Also you need to switch from your CCI400 primers the the magnum CCI450 primers; it makes a difference. I would also suggest you switch to an H-2 or ST-3 buffer. It will increase bolt dwell time and improve cycling. If needed I can go back into my research and show you where it is recommended by AAC in their data sheets.

I'm at work now and don't have access to my load data but I can tell you the buffer and the proper primers brought it all together for me when I was going through what you are now.

Actually I was able to find to AAC reference document here: http://www.advanced-armament.com/assets/images/pdf/manuals/300BLK-AACUpper-MiniBro.pdf

Let me know if there is anything I can do.
__________________
"The society that separates its scholars from its warriors will have its thinking done by cowards and its fighting by fools."
Thucydides circa 460 bc - c. 400 bc
oO_Rogue_Oo is offline  
 
Reply With Quote
Old 07-28-2015, 11:44 PM   #8
Feedback Score: 0 reviews
 
Wallace's Avatar
 
Join Date: Feb 2015
Posts: 198
Liked 50 Times on 36 Posts

Default

Thank you sir I appreciate it. My rifle shoots factory subs very well like a dream. I'm using the same bullet type as the Hornady 208 subs the only difference between my ammo and hornadys factory is the powder and possibly the primer. I'm going to check into a buffer though to see if it helps. I like switching between subsonic and supersonic so I want the system to shoot both very well.
Wallace is offline  
 
Reply With Quote
Old 07-29-2015, 02:37 AM   #9
Feedback Score: 0 reviews
 
oO_Rogue_Oo's Avatar
 
Join Date: Feb 2014
Location: Central MS
Posts: 350
Liked 160 Times on 123 Posts
Likes Given: 16

Default

Quote:
Originally Posted by Wallace View Post
Thank you sir I appreciate it. My rifle shoots factory subs very well like a dream. I'm using the same bullet type as the Hornady 208 subs the only difference between my ammo and hornadys factory is the powder and possibly the primer. I'm going to check into a buffer though to see if it helps. I like switching between subsonic and supersonic so I want the system to shoot both very well.
The H-2 buffer will shoot supersonics just as well; no worries there.
If you look at your load data carefully you should see where it specs magnum primers. They do make a difference.
I can feel your pain though I shoot the same bullet and almost gave up on it and went to 220gr until I figured it out. I was using CCI400 primers at the time too.
__________________
"The society that separates its scholars from its warriors will have its thinking done by cowards and its fighting by fools."
Thucydides circa 460 bc - c. 400 bc
oO_Rogue_Oo is offline  
 
Reply With Quote
Old 07-29-2015, 02:44 AM   #10
Feedback Score: 0 reviews
 
oO_Rogue_Oo's Avatar
 
Join Date: Feb 2014
Location: Central MS
Posts: 350
Liked 160 Times on 123 Posts
Likes Given: 16

Default

Another thing to think about is your crimp. I use a Lee Factory Crimp Die and put a medium crimp on my ammo. I do it for consistent pressures. As I understand it the crimp increases chamber pressure a little; ....................... may help

EDIT: Must admit I've never fired the Hornady factory ammo so I don't know if they crimp or not. It was just a thought


__________________
"The society that separates its scholars from its warriors will have its thinking done by cowards and its fighting by fools."
Thucydides circa 460 bc - c. 400 bc
oO_Rogue_Oo is offline  
 
Reply With Quote
Reply

Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Firearms Forum Replies Last Post
300 whisper PAgunslinger DIY Projects 3 02-26-2015 04:23 PM
How to "Ghost Load" or "Carrier Load" or "Float a Round" a Shotgun Amsdorf General Shotgun Discussion 19 02-21-2014 05:35 AM
Load Help tnel74 Ammunition & Reloading 10 01-03-2014 05:18 AM
Gamo Recon Whisper grouping FullautoUSA Range Report 7 11-11-2012 03:16 AM
300 Fireball / Whisper upper Txhillbilly AR-15 Discussion 6 11-22-2010 10:47 PM