ForeverArmed
member
- Joined
- Jan 4, 2007
- Messages
- 191
Thanks for the additional responses, guys. (And good shooting there, AK103K!)
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=1
It's a long one but makes for some very enlightening reading. Of course I was already aware that 10-shot groups are better for determining statistical accuracy than 3-shot groups, but there's a lot of great info in that thread about different ammo types.
Indeed, as you just pointed out, the difference between a FF and non-FF barrel seems to be quite large. Here's what one of Molon's tests showed (from page 8 of the above thread):
If a non-FF is getting 1.5-2" @ 100 yards with from a rest with handloads, then maybe I'm getting about all I can out of the ammo I have.
Interestingly, I also found this on that thread (my emphasis in bold):
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=7
Now if someone is getting around 2.5" groups with factory M193 from a free-floated barrel when shooting from a bench rest, then the chances of me doing much better from a semi-rested position seem somewhat remote. (As the above thread shows, much better results were obtained with handloads.)
I really am beginning to think the ammo is the main factor. I'm sure my technique is also a part of it, but I'm being as careful as possible when shooting these groups and, like I said in the first post, I'm not seeing much movement of the sight picture through the scope except for my heartbeat. And then there are the issues with the trigger, FF versus non-FF, etc.
One reason I'm concerned about the accuracy of my ARs that I want to be able to effectively gauge my own progress as a shooter. It's tough to decide what works and what doesn't when you aren't sure what your ammo and rifle are capable of.
Once again, thanks for all the replies!
I believe I've hunted down that thread. Is this it?Don't Tread On Me said:I was on AR15.com when I came across a post by a fellow called "Molon" which had pictures of groups fired from a 1/7, 5.56, chrome lined, Govt profile barrel. One 10-shot group was free floated barrel, optics, 75gr match ammo - the other was not free floated. Free floated results were 1.2" @ 100 yards. The non FF'd was 1.9" @ 100 yards. Remember, both with match ammo.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=1
It's a long one but makes for some very enlightening reading. Of course I was already aware that 10-shot groups are better for determining statistical accuracy than 3-shot groups, but there's a lot of great info in that thread about different ammo types.
Indeed, as you just pointed out, the difference between a FF and non-FF barrel seems to be quite large. Here's what one of Molon's tests showed (from page 8 of the above thread):
Molon on AR15.com said:All testing was done from a bench rest at 100 yards and consisted of firing 10-shot groups of hand-loaded 52 grain Sierra MatchKings. A Leupold Vari-X III set at 25X magnification was used during testing.
The three 10-shot groups used for evaluation of the free-floated barrel measured 1.06”, 1.42” and 1.47’. The three groups were over-layed on each other using RSI Shooting Lab software to obtain a 30-round composite group. The mean radius for this composite group measured 0.36”.
The three 10-shot groups obtained from the non-free-floated barrel measured 1.68”, 1.89” and 1.95”. The mean radius of the 30-round composite group from this barrel measured 0.56”. The difference of 0.20” in mean radius at 100 yards is equivalent to approximately 0.6” or 0.6 MOA.
If a non-FF is getting 1.5-2" @ 100 yards with from a rest with handloads, then maybe I'm getting about all I can out of the ammo I have.
Interestingly, I also found this on that thread (my emphasis in bold):
That's from page 7 of the thread:Molon on AR15.com said:All shooting for this test was done at 100 yards from a bench rest. All groups consisted of ten shots each. For the first part of this test I decided to use the factory load of IMI M193. It is the most consistently accurate M193 load that I have come across. For the second part of the test I wanted to see how much I could improve on the accuracy of the IMI M193 load using hand-loaded 55 grain FMJ bullets. I choose to hand-load Hornady’s 55 grain FMJ-BT bullet for the same reason I used the IMI M193; it is the most accurate 55 grain FMJ bullet I have come across. The bases of these bullets appear to be much more uniform than the comparable bullet from other manufacturers. While I have obtained some singularly good groups using Hornday’s 55 grain bullet in the past, for some reason I have never created a 30-round composite group using this bullet.
Three 10-shot groups of the IMI M193 were fired from a free-floated 20” Colt HBAR with a 1:7” twist that is chrome lined and has a NATO chamber. (The Colt barrel was used because I’m just not willing to risk pressure issues by firing mil-spec M193 through one of my match chambered Krieger barrels.) Prior to obtaining those groups I fired a control load consisting of hand-loaded 77 grain Sierra MatchKings that measured 1.10”. The three groups of IMI M193 measured:
2.24”
2.59”
2.62”
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=7
Now if someone is getting around 2.5" groups with factory M193 from a free-floated barrel when shooting from a bench rest, then the chances of me doing much better from a semi-rested position seem somewhat remote. (As the above thread shows, much better results were obtained with handloads.)
I really am beginning to think the ammo is the main factor. I'm sure my technique is also a part of it, but I'm being as careful as possible when shooting these groups and, like I said in the first post, I'm not seeing much movement of the sight picture through the scope except for my heartbeat. And then there are the issues with the trigger, FF versus non-FF, etc.
One reason I'm concerned about the accuracy of my ARs that I want to be able to effectively gauge my own progress as a shooter. It's tough to decide what works and what doesn't when you aren't sure what your ammo and rifle are capable of.
Once again, thanks for all the replies!