First shot From AR is high right of rest of group. What gives?

Hellgate

Member
I was sighting in and shooting 5 shot groups on a sand bag rest @ 100yds. I noticed that beginning each group the first round went high & right of the other 4. Roughly .5-1.5" high and .5 tp 1 inch right. I repeated it several times Using the bolt release to chamber the first round. Once I saw the pattern I varied the chambering of the first round by trying full mags, only 5 in the mag, first round on the right, first round on the left, first round put in the chamber by hand and bolt eased over it, first round chambered by hitting the bolt release. The only thing I forgot to do was to pull the charging handle all the way back and let it slam home. This is with the Sierra 65gr Game King over 24grs W748 OAL 2.25", Fed 205 primer in weighed Federal mil spec brass. When I shot some 52 & 53gr match bullets I did not notice much of a difference in first round POI. The reason this is bothering me is I want an AR calling gun that throws the first round into the same group. The first shot is usually the one that counts but I've hit several on the 2nd, 3rd and in one case the 12th shot. What do I need to do to fix this? The upper was recently rebarreled with a CobraTac 16" nitrided SS match HBAR 1:8. Without the flier I'm getting 0.6-0.8" groups with the 65gr GK and in the .3s & .4s with the 52gr match bullet. The barrel was warm.
 
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Wish I had a ready or easy suggestion for this one....I'm assuming that you are not cleaning the barrel between five shot strings and since they are reloads, there shouldn't be any difference between rounds from that standpoint...All I can suggest it to find someone, if you don't have one, with a bore scope and thoroughly inspect the barrel, especially in the chamber area for any kind of anomaly that might be present that would affect that first round...A tool mark that gets filled in with powder residue on that first round is the only thing that comes to mind, but it would be impossible to see with out a scope...
 
Any reason your stuck on the 65 gameking? Unless you need the windbucking ability I wouldn't go with something as heavy. If you're not getting the flier with the lighter bullets i'd go with those.

EDIT: 3-4" groups with the 52's? Hmm, obviously you don't want to use those. Have you contacted the barrel manufacturer? Might be a good call to make.
 
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Originally Posted By: LARUEminatiAny reason your stuck on the 65 gameking? Unless you need the windbucking ability I wouldn't go with something as heavy. If you're not getting the flier with the lighter bullets i'd go with those.

EDIT: 3-4" groups with the 52's? Hmm, obviously you don't want to use those. Have you contacted the barrel manufacturer? Might be a good call to make.

He dropped the decimal and is referring to 0.3 and 0.4.

That first round thing shows up in some barrels and I've never seen rhyme nor reason other than just stripping off the top one they shoot well. My WAG is that I figure that something is changing the rate of the BCG velocity going home and not settling in. It's possible to help things out you could lap the lugs, Ritch was telling me about that one, plus make sure the upper is squared.

Greg
 
The reason for the 65 GK was because it shot better than the 60gr Hornady SP, 60gr Vmax, 68gr Hornady HP Match. I'd like to use a heavier bullet that isn't stopped by a shoulder bone or hind leg in case of poor shot placement or a running away shot. The barrel was installed on a SAA upper.

The group from the 52gr Hornady HP match was 0.6", minus the first shot flier it was 0.25".

Next range session I'll pull the charging handle all the way back and let it slam home to see if that chambers similarly to actual firing. If that doesn't help I'll use the lighter bullet.
 
Between the group shots are you letting the barrel cool back down to get a "cold bore shot" each time?
Are you cleaning the rifle between group shootings? Have you tried loading just one bullet with out the magazine?
 
so if you're high right, and you still want to have kill accuracy from all your shots with those heavies... why dont you adjust your crosshairs just a little low & left

you have the potential to reduce the high right first round by ½ of its varience from your point of aim and still have the rest of your follow up shots be more than reasonably accurate for hunting within 200 yds.

just thinking out loud
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Originally Posted By: Plant.Oneso if you're high right, and you still want to have kill accuracy from all your shots with those heavies... why dont you adjust your crosshairs just a little low & left

you have the potential to reduce the high right first round by ½ of its varience from your point of aim and still have the rest of your follow up shots be more than reasonably accurate for hunting within 200 yds.

just thinking out loud
smile.gif

if one of the tires on you truck was low would you let some air out of the other 3 to compensate?
also just thinking out loud.
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they end may not always justify the means, but there's time when it very validly can.

if that one tire was only capable of holding a specific amount of air and lowering the PSI on the other three is what it took to level the load - absolutely and without hesitation - especially if the other three tires were still within their inflation spec.

while i agree its not a perfect solution, sometimes to achieve a goal you need to go a little non-conventional.



however... adjusting the point of impact to compensate for the center of a firearm's group with a specific ammo isnt way out in left field by any means. If you can do so, and still maintain vital zone kill shot accuracy, its a valid solution if nothing else presents itself.

and in this case with the worst variance stated on the flyer is a 1.5" from point of aim, reducing that down to 3/4" would definitely make it more than hunting accurate and keep the rest of the tighter grouping shots within about the same distance from center, albeit in the opposite direction.

again, i fully agree, its not anything of an ideal solution, but if nothing else presented itself ( via further load development, adjusting the chambering/bolt seating process, etc) it may well allow the OP to satisfy his desire to keep using the heavy bullets and still maintain a reasonable amount of kill zone hunting accuracy that falls well within the limits usually put forth in the MPBR scope adjustment theory.
 
Originally Posted By: SlickerThanSnot

just thinking out loud
smile.gif

if one of the tires on you truck was low would you let some air out of the other 3 to compensate?
also just thinking out loud.
smile.gif
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Originally Posted By: BrowndiabloBetween the group shots are you letting the barrel cool back down to get a "cold bore shot" each time?
Are you cleaning the rifle between group shootings? Have you tried loading just one bullet with out the magazine?

I was not letting the gun cool down but was shooting at a steady, fairly slow rate. Maybe 5 shots in a minute, reload mag and repeat. I'd say the gun was "warm" but not hot. There were no cold bore shots.

I'm pretty anal and really, really don't want two POIs. I may do the sight adjustment if I can get the first shot a little closer.
 
magazine size?

what I'm getting at is if this is the 1st round from a 5 round mag, does it go away if you only load 4 rounds in it?

or are this with a larger mag that's no where near being loaded to capacity?

also, does this manifest with only one mag or with every mag used?
 
I was mainly using one 20 round mag (Lancer; semi transparent). I tried a full mag, only 5 rounds in the mag, first round on the left, and first round on the right. There might be a little change in windage on the first shot with the round being on the right vs left but the elevation was still the same.
 
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The first barrel I bought for my 223 SBR did the same thing. I swapped scopes, used a different lower, bolt, mags, ammo, with and without the suppressor and it still threw the first round....about 1.5" at 50 yards! I tried everything that you did from easing the bolt down on a chambered round to letting it slap. Left and right side of mags and even swapped followers and springs between mags to see if that helped. In the end, a new barrel solved the problem.
 
Kingzero,
It's a pretty new barrel. I had been just hitting the bolt carrier release button but I'll pray that pulling the charging handle all the way back and letting it slam home will work. I'll also try two more brands of mag besides the Lancer polymer (Pmag & generic steel).
 
Went to the range today. Tried pulling the charging handle all the way back and letting it slam home and still the first round fliers. I did get a little better grouping with a generic (unlabled manufacturer) steel mag with the round on the right but it could just be a tease. Will try again next session. I just had this upper rebarreled with a match grade barrel too.
 
Handguard is a Magpul M-LOK. I don't know about the barrel nut. The rifle was barreled by the barrel maker. I am keeping the resting points the same on each round (no change in sand bag contact points with the rifle.
 
Well, the only thing I can think might cause a first-round flyer would be a heat-related issue or something shifting due to recoil. On any other rifle, it would suggest a bedding issue. Since its an AR, I can only guess your handguard is putting uneven pressure on the barrel somehow. This might sound stupid, but next range session, pop the handguard off and try making a few groups. It might be a bit awkward, but you can either use a mag with a ranger plate as a rest, or load it one round at a time and rest it on the mag well. Anyway, good luck and try not to burn your fingers!
 
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