What kind of performance are you guys getting out of your 16 inch 1/7 barrels with M193?  Is M855 really anymore accurate than M193 out of your 1/7's?  My first AR was a 16 inch 1/9 HBAR but I sold that and just purchased a 6920.  

I read the ammo oracle and it says that it is best to only stabilize the bullet the minimum amount required for purposes of accuracy.  So I am wondering if a 1/7 twist will shoot M193 very well.

I would prefer to stick with either M193 or M855 for logistical / economic reasons.  I am considering trying out some heavier 75 - 77 grain bullets, only problem is I can't afford to stock up on them significantly and I don't want to have to re-zero, just want to stick with the same stuff.  


Anyway, what kind of accuracy are you guys getting with M193 and M855 out of your 1/7 barrels?  Anyone who can post some range results / groupings would be highly appreciated.  


Thanks for any input and advice.    




ETA:

OK, I think it boils down to one simple question.  Anyone who knows or wants to take a gander please fill in the blanks:



M193 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel.


M855 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel.

I shot a sub MOA three shot group with fliers opening it to 2.5" for a total of five shots at 100 yards. Rifle was a 1/7 C/L HBAR LMT MRP and ammo was Remington 55gr FMJ.

That was with an aimpoint. Plenty accurate for that rifles intended pupose.

Well I think M193 must be alright then.  I wonder how much that group would close had the barrel been a 1/9 twist?  Probably not enough to matter for your average shooter?



ETA:

BTW, that's better than I could do with a 1/9 HBAR.  That's me of course, not the rifle.

It probably wouldn't have been any better, and groups are based off the total, not the best 3 rounds.  Like CJ said, its a 2.5" group, and at least he is honest enough to give that.  Most people usually make up numbers based off what they have heard other people shoot.

Your weapon will probably be more accurate than you are, with just about all ammo.


There is nothing wrong with stocking up on XM193, its good ammo.

Not a 6920 but..........I had a 16" Bushy Dissy that I could shoot 1.5" (iron sights) groups at 100 meters.  It was a 1/9 twist.  I now have a 1/7 16" Middy, and I can hold 2.5" groups.  These groups have all been shot with XM193 ammo.  So there may be some truth to what you are suggesting, but I consider the difference marginal.  The ability to shoot a wider selection of ammo keeps me with the 1/7.  I also shot 3 rnds of some Winchester 45 gn. varmint stuff, and I kept all 3 in a 2 inch group out of the 1/7.  Wow, 45 gn stuff out of a 1/7?  Yes, that's what I thought after shooting the 3 shots.

Three rounds is 3/5ths of a group.

Quoted: It probably wouldn't have been any better, and groups are based off the total, not the best 3 rounds.  Like CJ said, its a 2.5" group, and at least he is honest enough to give that.  Most people usually make up numbers based off what they have heard other people shoot. Your weapon will probably be more accurate than you are, with just about all ammo. There is nothing wrong with stocking up on XM193, its good ammo.

You don't like me do you?

I think it would have shot under two inches easily, but I was shooting using the monopod as a rest, with an aimpoint and a heavy trigger. I was actually surprised how well it shot. The fliers were my fault, although I was on track for a better than average group, I am sure.

1/7, 1/9.....none of us are likely to notice the difference. I like 1/7 because it gives me options.

Quoted: Three rounds is 3/5ths of a group.

The 3 shots of 45gn stuff I was refering to where given to me by a fellow watching me.  I was surprised that the light stuff performed so well out of a 1/7.  He only gave me 3 rnds, or I would of shot a 5 shot group.  So 3 rnds out of 3 = 3/3rds which is equal to 1 or in this case a 3 rnd shot group.

M193 that's actually M193 and not somebody's approximation of it (i.e. real GI stuff) is more accurate than just about all of us here-and I'm being generous in the idea that there are some fantastical, mystical, "zen marksmen" here.  How good are YOU?  (I'm not good enough yet, but that just means I need to budget more time and money for more practice. )  With a really good barrel and a really, really steady hand, you should be able to shoot sub MOA with M193 at 100m all the time.  That discounts the guy next to you whacking you with his brass, wind gusts, dry eyes, and everything else that can mess with your shooting though.

I firmly believe that basic M193 or M885 ammunition should be the standard that both marksmen and ammunition should be compared to.  With huge production plants dedicated to these two loads, and pretty rigorous quality standards applied to the finish products, GI ammunition should be so consistent as to constitute a baseline standard.  As long as M193 is available and affordable, go for it!  Why spend money on fancy stuff that may be microscopically more accurate but costs several times more?

Just my 2¢ worth...

M193 is 2 MOA ammo or so. I'm not impressed. I am gonna give it a go with some match ammo to see what me and the rifle are capable of.

Quoted: M193 that's actually M193 and not somebody's approximation of it (i.e. real GI stuff) is more accurate than just about all of us here-and I'm being generous in the idea that there are some fantastical, mystical, "zen marksmen" here.  How good are YOU?  (I'm not good enough yet, but that just means I need to budget more time and money for more practice. )  With a really good barrel and a really, really steady hand, you should be able to shoot sub MOA with M193 at 100m all the time.  That discounts the guy next to you whacking you with his brass, wind gusts, dry eyes, and everything else that can mess with your shooting though. I firmly believe that basic M193 or M885 ammunition should be the standard that both marksmen and ammunition should be compared to.  With huge production plants dedicated to these two loads, and pretty rigorous quality standards applied to the finish products, GI ammunition should be so consistent as to constitute a baseline standard.  As long as M193 is available and affordable, go for it!  Why spend money on fancy stuff that may be microscopically more accurate but costs several times more? Just my 2¢ worth...

I agree with you whole-heartedly.  I have been shooting almost exclusively M193 out of my 1/9 barrel.  My concern though is what is M193 capable of out of a 1/7 barrel.  Do you think this statement holds true for 1/7 barrels as well?  And do you think that I should switch to M855 now that I have a 1/7 barrel?  If so then I am in trouble, because I have four cases of M193 stored and one that I am shooting through, and very little M855.  I don't know if I can afford the switch right now.  But if M193 is going to give me 2-2.5 MOA out of a 1/7 barrel then I don't know that I am happy with that.  I am probably a 2-3 MOA shooter right now (in perfect conditions) in all honesty with iron sights (I am saving for some good glass right now, probably an acog next january if I'm lucky), but I expect to improve and I don't want my choice of ammunition to hold me back.

I don't get this "more accurate than you are" stuff.

I never shot anything other than xm193 out of a rack grade colt carbine.  2.5 inches, ho hum.

Then, thanks to 1911builder, I shot match grade 77grain out of a schillen barrel, with an accuracy speaks trigger.

.75 inches, with irons!

So, in order to find out how accurate YOU are, you have to have stuff that is MUCH more accurate than you are.

How can you ever learn how to drive a Porsche, if all you got is a VW Beetle?????

If you wanna shoot better, get the best equipment you can!

OK, I think it boils down to one simple question.  Anyone who knows or wants to take a gander please fill in the blanks:



M193 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel.


M855 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel.

Quoted: If so then I am in trouble, because I have four cases of M193 stored

You could always solve this little problem and donate it to me.

I shot 5 shots, two through the same hole with the other three "flyers".  My rifle shoot about .25" all day long if not for the "flyers" .

Quoted: I shot 5 shots, two through the same hole with the other three "flyers".  My rifle shoot about .25" all day long if not for the "flyers" .

If you are refferring to my post, I make a distinction between fliers that I caused, and ones that the rifle caused. In this case my sight alignment and trigger manipulation was the major cause of the fliers. If the rifle caused it, its not really a flier, just a shitty group.

Quoted: Quoted: I shot 5 shots, two through the same hole with the other three "flyers".  My rifle shoot about .25" all day long if not for the "flyers" . If you are refferring to my post, I make a distinction between fliers that I caused, and ones that the rifle caused. In this case my sight alignment and trigger manipulation was the major cause of the fliers. If the rifle caused it, its not really a flier, just a shitty group.

I understand what your talking about C_J.  


We are not talking about how good the groups WE can shoot are, we are discussing how good the groups based upon the rifle and ammo.   Your missing the point.

Thats why I made the distinction that I Was the cause of those fliers. Then I speculated on the accuracy I had observed from M193, which tends to be around 2 MOA. From a floated gun. Nothing to brag about. I was on track for a REALLY good group though.

Quoted: I don't get this "more accurate than you are" stuff. I never shot anything other than xm193 out of a rack grade colt carbine.  2.5 inches, ho hum. Then, thanks to 1911builder, I shot match grade 77grain out of a schillen barrel, with an accuracy speaks trigger. .75 inches, with irons! So, in order to find out how accurate YOU are, you have to have stuff that is MUCH more accurate than you are. How can you ever learn how to drive a Porsche, if all you got is a VW Beetle????? If you wanna shoot better, get the best equipment you can!

You didn't do (or at least you didn't report) a proper scientific comparison here.  You changed many variables at once, so scientifically you cannot tell whether it was the wonderful barrel, the great trigger, or the fancy ammo that tightened up your groups.  What can you do with M193 out of the Schillen barrel?  Have you tried that?  I'm happy that you got to such small groups over iron sights, but how much did each component contribute to the overall improvement?

If you put standard production M193 through an accuracy-test rifle (basically a bolt action on a huge barrel that's bolted to a solid base-the thing is NOT going to move at all!), you should get sub-MOA groups all the time-probably significantly sub-MOA.  Tweak that barrel for 77 gr. bullets and you should get somewhat tighter groups with 77 gr bullets at the same range due to their higher inertial and rotational mass.  

I don't think changing to a 1/7 barrel will make M193 any less accurate, either.  The faster spin from a 1/7 barrel won't do much more than make a 55 gr. bullet spin faster-it won't blow up like one of those fragile varmint bullets will, and the consistency of standard production GI bullets is good enough that you won't see much of a measureable difference, even through an accuracy-test rifle.

C_J, when I said "Your missing the point" I was refering to the post that was criticizing you, just in case you took me wrong.  I understand what you are saying and appreciate your input.


I guess I am just going to have to shoot the damn thing to get a definitive answer.  Just for shits and grins I will let you all know how it went when I get a chance to go.  



Thanks everybody for the info.

Quoted: OK, I think it boils down to one simple question.  Anyone who knows or wants to take a gander please fill in the blanks: M193 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel. M855 will average about ____ MOA out of a 1/9 barrel, and ____ MOA out of a 1/7 barrel.

That is a question with NO wrong answer.

Answers will depend on your lot of ammo (heck even the batch of bullets will make a difference), your particular rifle (barrel, bolt lockup, muzzle device), and most importantly the shooter.

I wouldn't worry about it - I'll bet your rifle+ammo combination will shoot better than you can so it's irrelevant.

6920 with 4x acog. 100 yards with sandbags, lc m855 1 to 2 inch groups, with q3131a 2 to 3 inch groups.  the m855 is consistantly more accurate.