Pistol gas subs, various bullets & powders, updated pg 6&7

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certifiable
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Pistol gas subs, various bullets & powders, updated pg 6&7

Post by certifiable »

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

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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"
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Last edited by certifiable on Thu Jul 24, 2014 1:31 am, edited 6 times in total.
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dead-bird
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Re: 220SMK subs using various powders

Post by dead-bird »

Nice data!
Retooferab
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Re: 220SMK subs using various powders

Post by Retooferab »

Nice, I've had better luck loading the smk to 2.10 oal.
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trook
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Re: 220SMK subs using various powders

Post by trook »

Thanks for all the info. Please explain the abbreviations in your notes.
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Re: 220SMK subs using various powders

Post by certifiable »

trook wrote:Thanks for all the info. Please explain the abbreviations in your notes.
BHO - Bolt Held Open on empty mag
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
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Re: 220SMK subs using various powders

Post by certifiable »

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."

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Retooferab
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Re: 220SMK subs using various powders

Post by Retooferab »

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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JoeHarley13
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Re: 220SMK subs using various powders

Post by JoeHarley13 »

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

Post by certifiable »

Updated data
"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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Re: 220SMK subs using various powders

Post by certifiable »

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.
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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
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