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Posted: 5/14/2009 6:16:13 PM EDT
| With its steel tip core, how accurate iss the SS109? |
Some of the best M855 that I have fired was produced by IMI. Here's a short evaluation of that ammuntition.
IMI M855 is loaded with a 62 grain FMJ bullet with a cannelure and has a steel penetrator. The ammunition is charged with "ball powder". The primers are sealed and crimped in placed. The bullet is also crimped in place and the case mouth is sealed with an asphalt sealant. It is easily distinguished from IMI M193 by the green painted bullet tip. 
Chronograph data was obtained using an Oehler 35P with "proof screen" technology. All velocities listed are muzzle velocities as calculated from instrumental velocities using Oehler's Ballistic Explorer software program. All strings of fire consisted of 10 shots each. 
Accuracy testing was performed using a free-floated 20" Colt HBAR. The barrel has a 1:7" twist, NATO chamber and is chrome lined. Accuracy testing was done from a distance of 100 yards shooting from a bench-rest. A 10-shot control-group was fired using 55 grain Sierra BlitzKings and had an extreme spread of 1.17". Three 10-shot groups of the IMI M855 were fired in a row with the following extreme spreads: 2.14" 3.01" 1.71" for a 10-shot average of 2.29". The best 10-shot group is pictured below. 
The three 10-shot groups were overlayed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for this composite group was 0.69". 
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Lower RH target, 10 shot group 100 yds, 16" 1 in 9 AR. One flier took a 2" group and made it a 3" group. Normally I load SS-109's with BLC2, but this day tried Varget. Bullets were pulled with heavy pull marks, came from Wideners. With my bullets I normally expect 2 1/2" groups at 100 yds. Not a target bullet by any means, but used to be a cheap blasting bullet. |
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The problem with with M855 is the steel penetrator. If it is perfectly centered and consistant each and every time, the penetrator is not a detriment to accuracy. That is not a given, so there are fliers attributed to bullet construction.
Lew Tippie (I know....) said he would rather shoot M193 even at 600 yards than M855 due to these unexplained fliers. |
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Molon,
Where are you getting IMI M855. I haven't seen the stuff in years. The best (most accurate) SS109/M855 I've ever shot was Hirtenberger (from Germany) but I haven't seen it in over 15 years, followed closely by IMI. It was far more accurate than the Lake City stuff. It was so accurate I used to use it in matches when I first converted from the M1A1 to the mouse gun back around '89 timeframe. Clinton put a ban on the import of that stuff and it disappeared over night. |
The ss109 isn't going to win any accuracy contest for sure. About 2 inches at 100 yards sounds about right. God knows what it would do at 200 or 300 yards. I only shoot mine at 50 yards as you can get an inch or less pretty consistently at that yardage. I only shoot it with iron sights, won't dignify it by using a scope and free float barrel as it won't help. 
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Quoted:
The ss109 isn't going to win any accuracy contest for sure. About 2 inches at 100 yards sounds about right. God knows what it would do at 200 or 300 yards. I only shoot mine at 50 yards as you can get an inch or less pretty consistently at that yardage. I only shoot it with iron sights, won't dignify it by using a scope and free float barrel as it won't help. My range has a steel plate at 180 yds that is aprox chest size. Off hand with open sights it is no problem to ring the gong with my SS-109 loads. To be fair, Win 55 gr FMJBT's will do the same. |
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