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First round from magazine a flyer

This is a discussion on First round from magazine a flyer within the The M14 forums, part of the M14 M1A Forum category; Guys: I have a 90s era SA M1A Supermatch, now scoped with a Leupold VX-R on a Sadlak Airborne mount. Solid mount, great sight picture. ...


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Old January 4th, 2017, 07:40 PM   #1
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First round from magazine a flyer

Guys:
I have a 90s era SA M1A Supermatch, now scoped with a Leupold VX-R on a Sadlak Airborne mount. Solid mount, great sight picture. The new sighting system has closed up my groups (old eyes and iron sights do not mix), which uncovered a new problem.

Today while testing several loads, I noted that the first round loaded from a (5 round) magazine consistently printed 3" out of the group at 10 o'clock. This flyer occurred in 8 of the 10 magazine loadings I fired. The groups otherwise were about 2.2" at 100 yds (ATC values ~0.85"), so the flyer was obviously out.

Load is Hornaday 150 FMJ over 41.3g IMR4895, CCI34 primer, IMI match cases (@ about 2510 fps). That is not my match load, just a 'practice' load.

The question is what might cause this 'first round' effect? I do not ride the op rod handle home, and the rounds are loaded in the magazine with case heads all the way aft in the magazine.

Any thoughts or suggestions are appreciated.

Thanks from Allen Humphrey
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Old January 4th, 2017, 07:57 PM   #2
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Cold bore first shots are always the least accurate.
I say this of course with cooling of the barrel between sets.
Seasoning a barrel will reduce this effect but the effect still remains.

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Old January 4th, 2017, 08:05 PM   #3
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In testing and targeting several thousand M14EBRs, I pretty much discounted the first and last rounds out of the Magazines.

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Old January 4th, 2017, 08:54 PM   #4
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Dutchman and EBR Builder:

Thanks for the responses.

The barrel is pretty well seasoned. I bought the rifle new, and it has about 3500 rounds through it at this point. Forgot to mention that I have moly coated ALL my bullets. When shooting today, i was maintaining a pace of about 2 rounds per minute, which i could almost maintain with a mag reload. I don't think the barrel got perceptibly cooler. It was warm but not hot.

EBR: so when shooting a match, how does one get around the 'first/last' issue? Does anyone know why this happens? I will say that the effect is much less with my 168g Sierra MK 'match' loadings. Does freebore play a role? Is this an oprod timing matter? Aside from seasoning, are there ways to minimize or eliminate the effect?

Any ideas or explanation for the consistent distance and direction of the flyers?

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Old January 4th, 2017, 08:56 PM   #5
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Guys,

I have a 2006 SA SM that seems to more often throw the last round out of a 10 round mag shooting 5 round groups out of the group but not by that much?

Sometimes the first round out of a cold (dry?) barrel goes who knows where so when I am shooting for groups usually shoot a warm up shot or two.

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Old January 5th, 2017, 03:24 AM   #6
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I pretty much eliminated that phenomenon with my rifles by de-buring and polishing the the underside of the feed lips on my mags.

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Old January 5th, 2017, 03:47 AM   #7
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I have heard of this before.

What is the physics behind this phenomenon? How would a DMR deal with this?

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Old January 5th, 2017, 08:18 AM   #8
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I would not "over-analyze" a Super Match using self moly coated 150's at 2500 fps. Especially with 3500 rounds down the tube. A 2.2" group is what I would expect from a Loaded model.

Your rifle most likely has a 1/10 twist, intended for heavier bullets at a healthy velocity.

How are the groups using Federal Gold Medal Match? Is the first round still a flier?

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Old January 5th, 2017, 08:26 AM   #9
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Quote:
Originally Posted by M11293 View Post
I have heard of this before.

What is the physics behind this phenomenon? How would a DMR deal with this?
A true "cold bore" shot can be as much as 2 moa different from subsequent shots. Long range snipers will often practice with only the cold bore shots, even if it means only one shot an hour. (I've heard stories of one shot per day). Separate dope is kept for follow up shots.

I don't believe the DMR role is expected to have the same type of cold bore accuracy as a sniper. They are usually integrated with a fire team.

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Old January 5th, 2017, 09:00 AM   #10
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At matches there are some practice shots that can warm up your bore.

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Old January 5th, 2017, 10:23 AM   #11
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nf1e: 800 grit paper? How are you polishing the feed lips? I have not felt burrs, but have not looked as closely as I might.

KurtC: To your point, I never noticed the effect with my 168g SMKs at 2700 when I was shooting competitively in matches. With iron sights, if I did my part, the rifle would put 10 rounds into 1.1" pretty consistently. Good enough to score 180+ on 5V matches. So bullet and velocity and standard deviation all play a role, and the lighter, non-match grade bullets are clearly inferior to SMKs. It was just odd that the first round out of the mag was way out, and always in the 9:30-10:30 direction.

Thanks all for the responses.

WJC

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Old January 5th, 2017, 02:34 PM   #12
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Quote:
Originally Posted by brianns View Post
At matches there are some practice shots that can warm up your bore.
I haven't shot matches in a long while --- back when I did, NRA Matches allowed 2 sighters per stage ---- DCM and DCM Leg Matches and the National Service Rifle Matches at Camp Perry (like the Presidents Match, etc.) did not allow for any sighters, the first shot out of the barrel was for record.
I was lucky in that my matched tuned M1As would put the first round within the grouping ability of the rifle/shooter.

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Old January 5th, 2017, 03:32 PM   #13
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Very dedicated and skilled HP shooter with M1A once told me he went through various magazines to find one that gave better accuracy than the others?? Not sure I understand that approach, but claimed it did make a difference and if he shot less than 485/500 he was disappointed. Claimed that if he did not find that "special" magazine his first shot would not be on call. Again, anyone know why the magazine would cause this??

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Old January 5th, 2017, 04:12 PM   #14
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Quote:
Originally Posted by wjcalhoun View Post
nf1e: 800 grit paper? How are you polishing the feed lips? I have not felt burrs, but have not looked as closely as I might.

KurtC: To your point, I never noticed the effect with my 168g SMKs at 2700 when I was shooting competitively in matches. With iron sights, if I did my part, the rifle would put 10 rounds into 1.1" pretty consistently. Good enough to score 180+ on 5V matches. So bullet and velocity and standard deviation all play a role, and the lighter, non-match grade bullets are clearly inferior to SMKs. It was just odd that the first round out of the mag was way out, and always in the 9:30-10:30 direction.

Thanks all for the responses.

WJC
I made up a solution to yucky chambers and mags years ago.

Took a ..308 casing, drilled out the flash hole and threaded to the same thread as my flexible pistol rod. Then threaded a machine screw into the hole from inside casing and secured with a lock nut.
I use this tool for polishing scratched chambers and prep magazine feed lips. I use whatever lapping compound is handy, usually 800 or 1000 grit. A few spins with the electric drill and it's done. A little polishing rouge on a bore mop and the underside of the feed lips are as smooth as a baby's butt.
I also clean up the mag follower by wire bushing on a wheel and buffing with rouge.
In my opinion this reduces the friction on both the first round and last out of the mag.
If I am shooting from a mag, I release the op rod by pulling all the way to the rear and letting her fly. I would never use the bolt lock as a release. This is not an AR.
After just over 50 years of shooting the M-14, I have found a few things that seem to help especially with first and last round flyers.
Before I came up with this idea, I used to number my mags and used the ones with the best performance. After this simple operation, all magazines seemed to be equal.





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Art

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Old January 9th, 2017, 04:57 PM   #15
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Art:
Thanks very much for the info, and the pictures.
I will also note that I don't see the 1st round effect nearly so much with my 20 round mags. I just happened to be using the 5 round mag and the 1st round effect was clear.

I wonder if the magazines owned by the friend of Instructor varied in the friction of the lips and follower?

Thanks again guys

WJC

Thanks from nf1e
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