Over the past couple of weeks I have been working up sub loads for the 220SMK using the various 300BLK compatible powders I have on hand.
The test gun is an AR platform assembled as below:
9" AAC barrel w/ pistol gas, port ID unknown
Colt M4 upper
DPMS semi BCG, unless otherwise noted
Seekins MCRS 9" FF hand guard
Seekins SP15 lower
DPMS LPK
Standard carbine buffer & spring
Nikon P22 scope at 7x
Groups were shot @ 50 yards and were 5 shots each except as noted
Cases were mixed year(unless otherwise noted) LC that I formed using Forster dies and were not annealed.
Functioning of the rifle is noted and all shots were w/o a suppressor attached
Elevation 1900' ASL, temp was 78 deg. F and an 11 mph cross wind
Ran some more today, 5/31/13. 82 deg. F
All groups were shot suppressed. The rifle cycled perfectly with each powder and the bolt locked back every time.
From the grouping, I would have to conclude that this rifle prefers an OAL of 2.173" rather than 2.100"
Pistol gas subs, various bullets & powders, updated pg 6&7
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Pistol gas subs, various bullets & powders, updated pg 6&7
Last edited by certifiable on Thu Jul 24, 2014 1:31 am, edited 6 times in total.
"America will never be destroyed from the outside.
If we falter and lose our freedoms, it will be because we destroyed ourselves."
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If we falter and lose our freedoms, it will be because we destroyed ourselves."
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Re: 220SMK subs using various powders
Nice data!
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Re: 220SMK subs using various powders
Nice, I've had better luck loading the smk to 2.10 oal.
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Re: 220SMK subs using various powders
Thanks for all the info. Please explain the abbreviations in your notes.
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Re: 220SMK subs using various powders
BHO - Bolt Held Open on empty magtrook wrote:Thanks for all the info. Please explain the abbreviations in your notes.
FA BCG - Full auto bolt carrier group
SA BCG - Semi auto bolt carrier group
This weekend I will run another string of each load to verify data.
I will also run a string of each thru my sdn6 checking for cycling & BHO of all powders and a third string
@ 2.100" just for SnG
"America will never be destroyed from the outside.
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
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Re: 220SMK subs using various powders
Edited for content
"America will never be destroyed from the outside.
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
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Re: 220SMK subs using various powders
Let us know what you find and good luck!
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well armed lamb contesting the vote." Ben Franklin
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Re: 220SMK subs using various powders
Great data, I only have H110 & Lilgun. Looks like H110 will be the way to go with 220gr SMK.
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Re: 220SMK subs using various powders
Updated data
"America will never be destroyed from the outside.
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
- certifiable
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- Posts: 1766
- Joined: Mon Nov 26, 2012 8:14 pm
- Location: Kansas
Re: 220SMK subs using various powders
Shot some more of the 220's over 9.8 gr A5744.
This time I charged the cases using my Hornady powder measure with the pistol rotor & insert.
I did not chrony them as the wind was bad today.
5- 5 shot groups at 50 yds, 3 groups w/o suppressor and 2 groups with.
Same 9" AR, suppressor used was SDN6 attached via Brakeout
edit: buffer changed to spikes T2 and used FA BCG. All rounds cycled flawlessly and got BHO Everytime.
This time I charged the cases using my Hornady powder measure with the pistol rotor & insert.
I did not chrony them as the wind was bad today.
5- 5 shot groups at 50 yds, 3 groups w/o suppressor and 2 groups with.
Same 9" AR, suppressor used was SDN6 attached via Brakeout
edit: buffer changed to spikes T2 and used FA BCG. All rounds cycled flawlessly and got BHO Everytime.
Last edited by certifiable on Sat Jun 22, 2013 1:48 pm, edited 2 times in total.
"America will never be destroyed from the outside.
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
If we falter and lose our freedoms, it will be because we destroyed ourselves."
Abraham Lincoln
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