US Army M24 accuracy claims

[Roddy]

I saw this on Wikipedia but part of it was originally from sniper central.com:

According to MIL-R-71126(AR), the M24 shall achieve the accuracy results stated below when using M118 Special Ball and fired from a Government approved machine rest. The average mean radius, calculated using 5 targets of 10 shots each, shall be less than or equal to the following values:[1]

200 yards (183 m): 2.6 inches (1.242 MOA)
200 metres (219 yd): 2.8 inches (1.223 MOA)
300 yards (274 m): 3.8 inches (1.146 MOA)
If these accuracy standards are not met the barrel is considered worn out.

The actual rifle requirements for accuracy were .35 MOA from a machine rest and according to Major John Mende (ret.) this accuracy had to be maintained to 10,000 rounds. He stated, "Interesting side note was there was a 10,000 round requirement for the barrel to maintain the original accuracy. In fact after some 10,000 round tests we discovered the accuracy improved. A few barrels were tested past 20,000 and accuracy never went below the original accuracy requirement."

So what's going on here. It seems to me they got almost four times the accuracy they wanted. Is the 0.35 MOA a typo or is Major John Mende just trying to sell the M24? 0.35 MOA is exceptional accuracy for any factory rifle especially for ten round groups.

They say ten rounds but here is a test target with three rounds:

And I thought 10,000 rounds was about the useful barrel life for a .308 precision rifle but he is saying they went 20,000 rounds. Do they have to re cut the chambers to go that long?

The article seems a bit fishy and contradictory but interesting if true.

 

[BadAsMo]

Key word is radius.
Not to be confused with extreme spread.

 

[Mystic Precision]

The M24's were pretty much "custom" made using match barrels so delivering sub MOA accuracy would be the norm. Each of these Rems was rebuilt inhouse and pretty much showed the way to "blueprint" a Rem 700. Given the ammo specs (keep reading down the wiki post), moa'ish out to 1000yds under ideal condition, would certainly be possible.

The ammo pressure for the M118LR is very low compared to what is run in many competitions today. Dropping pressure that 10 to 20,000psi does wonders for extending bore life. Could you get a barrel that somehow lasted longer then the norm? Sure. Get a barrel into a busy "work day" and drive as much ammo as you can find, that barrel is going to wear out much much faster.

Although, the ammo and system was rated and tested to 1000yds, I have read alot of anecdotal posts that the 308 stopped being affective around 800yds. Maybe they were refering to drift becoming more then they could easily adjust for??? Or maybe the average rifle was more worn then they were allowed to fix????

Either way, a barrel will last as long as it lasts. The steel is the problem and each batch can and will vary. Some have just the right voodoo to work amazing... some not so much. Rifling style is certainly not the reason.

So I take this is an average of averages from an industrial machine with "good enough" standards.

I have had the pleasure of shooting beside a markmanship training group using the new M24E1's in 300WM. Given their age, I expect they had the full range of experiences but at 1000yds, you do not want to be standing there. For their intended role, those rifles and brown box ammo, shot really well.. and when all of these gents get schooled, they are going to be very impressive at distance.

10 ring is 10", 9 ring is 20"... very few shots went outside that 9 ring from the shooters while I was in the pits.... and it was windy.

Jerry

 

[kirill]

Although, the ammo and system was rated and tested to 1000yds, I have read alot of anecdotal posts that the 308 stopped being affective around 800yds. Maybe they were refering to drift becoming more then they could easily adjust for??? Or maybe the average rifle was more worn then they were allowed to fix????

One of the latest posts on Accuracy Tech talks about the transition between supersonic and subsonic speed, which happens to be right around 800yd for a 168gr 308. He specifically mentions the limited 800yd range.

My $0.02

 

[Potashminer]

Average Mean Radius is not group size!! First you measure heights and find vertical center of group. Then measure horizontals to get horizontal center of group. Then measure distance from center of each hole to group center. "group" size measures farthest to farthest holes and ignores the rest. Mean radius tells you how tight, on average, that the ammunition or rifle will cluster their shots.

 

[J996]

M118LR uses a 175 SMK and is plenty effective past 800 yds.

 

[Roddy]

M118LR uses a 175 SMK and is plenty effective past 800 yds.

I think the US military's definition of effective range is at least a 50% probability of getting a hit. In Sgt. Hancock's case I guess he definitely showed that to be over 800 yards!

I guess I am just misreading the group radius measurement. I thought it sounded a bit unrealistic and I don't know where the group pictures are from. That could be the best of a platoon's day of shooting for all I know.

 

[J996]

I think the US military's definition of effective range is at least a 50% probability of getting a hit. In Sgt. Hancock's case I guess he definitely showed that to be over 800 yards!

I guess I am just misreading the group radius measurement. I thought it sounded a bit unrealistic and I don't know where the group pictures are from. That could be the best of a platoon's day of shooting for all I know.

Here's your answer, same group pic as you found above:

http://www.snipercentral.com/history-m118-ammunition/

"When I went through the US Army Sniper School at Ft. Benning, and during my years as a sniper after that, I only used the M118 SB ammunition and I can attest to the questionable quality. The main problem was the inconsistency of the ammo. There were times where we would shoot a 1.5″ group at 500 yards and then with a different lot shoot a 5″ group at 500 yards. Because of this we tended to try and search at the good lots, if possible, when ammo was issued. The M24’s we used were great rifles and they tended to shoot better than 1 MOA with M118, and that was more of a testament to the quality of the rifle than the ammo. When we would switch to commercial match ammo, sub .5 MOA was no problem with our M24’s."

 

[Mystic Precision]

One of the latest posts on Accuracy Tech talks about the transition between supersonic and subsonic speed, which happens to be right around 800yd for a 168gr 308. He specifically mentions the limited 800yd range.

My $0.02

Sierra 175gr MK has been the dominant bullet used in this set up since the beginning... no issues with this bullet going at least 1300yds out

Jerry

 

[peterdobson]

We shot Black Hills .308 w. newer 175 SMK ballistic tip reliably to 1025 yards in AI bolt and new Daniel Defense semi @ CORE Training Center last week.

Great fun and have to admit our illustrious mod. has been, for the most part, spot-on as regards PRS. Now we need more ranges!

Regards,

Peter