Home Forums Hunting & Shooting Ask The Gunwriters Autoloader rifle- first shot out of group?

Outdoor Life article stated that the first shot, chambered manually, will have a different poi than follow up shots chambered automatically because they do not seat the same. ??
Any experience with this?

I know that a clean barrel can cause a different poi for the first shot, but that is not what is in question here.

I always let the bolt fly from the rear when chambering the first round. Would that eliminate this difference, if it exists?

Don't know if that is the cause for sure but the first shot out of my 740 in 280 is always about 1 1/2" higher than the group! Still within a MOE or MOD though!!!

Is the barrel clean for that first shot, and is there any oil in it?

Do you chamber the round gently or let it slam home?

had a winchester mod. 100 in 308.it would always throw first shot out of the group clean or dirty barrel made know difference. next three shots would snug right up into a nice group. always suspected bedding.

Ed

I always fire the 1st shot 3rd, to eliminate the problem.

Good idea! I'll have give that a try.

Clean or dirty it doesn't seem to matter.
Always let the bolt chamber the round w/ return spring pressure, ie let it slam.

I do a ton of shooting of AR rifles and I have not noticed any difference in poi weather the round was chambered manually or automatically. I use one chambered in 243wssm for long range hunting and have had no issues.

In two different BARS, a 30-06 and 300 Win, I have not seen a difference first to second shot.

-Z

It is my understanding that this is a common problem with some auto-loading firearms, whether they be rifles, pistols, or rimfire arms. It is not limited to any particular brand or model or caliber.

Sometimes the extent of the problem is small enough to be ignored, as Ulve said above. Sometimes it is significant and poses a real problem.

It has nothing to do with clean barrel versus dirty barrel, or oil in the barrel. Those are different causes and effects. I don't believe it has much to do with bedding, either.

Sometimes the problem is reduced or eliminated by letting the bolt slam home on the first round; sometimes not.

I have seen this problem in my own M-1 Carbine, in a friend's M-1911 .45, and in an older Marlin M-60 .22 rifle.

This potential problem is one of the "Con's" on the list of various Pro's and Con's of selecting a semi-auto action firearm.

I believe that sometimes a switch of ammo can reduce or eliminate the problem. If that didn't work I would trade the particular firearm in on something else.

This comment was posted on another forum. Others agreed, but nobody seemed to have a good answer or solution.


EthanP
August 13, 2013 at 03:13

I can only say that most, but by no means all, of my semi-auto’s seem to have a different point of impact between the first round and the rest of the mag. I do’t know why. I never encounter this with a revolver.

This is a different problem, but one that few people have considered, regarding semi-auto rifles:

Frank Crary (fcraryucsu.Colorado.EDU) wrote:

Why would the magazine effect accuracy?

Many M14/M1A competition service rifles do not shoot to the same point
with different magazines. The reason is the magazines do not pre-load
the receiver with the same amount of pressure at the same points for
each one. Tests have shown that some rifles will change point of impact
as much as 1 MOA between magazines. You need to get a few magazines that
let your rifle shoot to the same point of impact. Plus, it's difficult
to keep the magazine in exactly the same place from shot to shot. Other
tests have shown that M1A/M14 rifles shoot more accurately without the
magazine installed. Even the M1 Garand shoots better without a clip in
it; just used single-shot.

So, for a hunting rifle, zero your rifle by shooting one shot at a time, single-loading, and letting the bullet seat as you usually do.

Once zero'd, shoot three rounds from the magazine, to see where the next shots will group, in case a follow-up is needed.

For some interesting reading, google "First Shot Flyer Problem".

You can read about this problem occurring in many different firearms, including Ruger 10/22s, so no particular model is guaranteed to be immune, it seems.

If I had a rifle doing that the solution would be to get rid of the frigging thing.

One solution I read concerning this problem as related to the M1 Garand is to apply a crimp when reloading. I have tried this and it seemed to improve the first shot out of group. Might try this. I believe the gun is recoiling rather than being manually operated affects the bullet impact.
358win

Was the second shot from a cold barrel as well?

Had a few BARS and one would do that, but adding a piece of rubber under the fore-end screw was the cure.

Ruger 22...dang near perfect.

I handloaded for and shot a good bit a then new Remington 740 in 30'06 back in the late 50's and the early 60's. After a few years, I bought a Browning BAR in 7 Remingto Magnum. I also handloaded and shot rifle a good bit out to 300 yds. In the mid 70's, I had, and handloaded for a Colt AR-15 Sporter.
None of the above rifle shot high for their first shot. I did feed them from the magazine. I learned early on that trying to place a round in the chamber sometimes didn't allow me to easily close the bolt.
I've seen plenty of rifles shoot out of zero if the barrel was clean and heavily oiled. I've even seen rifles that were too clean shoot much larger groups until the barrel was fouled, but the zero was constant. But never a semi auto that threw the first shot. Don't think I know, or have known anyone, who has had that problem with a semi auto centerfire.
I have even seen one rifle that would change zero after 10-15 rds. That rifle had a cheap synthetic stock whose bedding would compress as it was fired. After having it glass bedded twice, I sold it. E

In rifles it's usually due to a condition called "bolt overrun".

This happens when the difference between the front of the bolt and the back of the lugs is greater than about 2 thou less than the distance between the front of the lug seats and the face of the barrel.

Auto rifles are headspaced with the lugs bearing fully against the lugs seats. If that leaves a space between the front of the bolt and the barrel face greater than about 2 thou, the bolt sizes the cartridge down, changing headspace. This differently headspaced cartridge shoots to a different point of impact. The heavier the reciprocating mass, the more pronounced this effect.

On an AR, it's easy to feel this before you barrel just by sticking a bolt in the extension and seeing if you have any back-n-forth play when the bolt is in the locked position.

The cure is to get someone to do a better job installing the barrel.

BarryC,

Thanks for that good explanation. Many people recognize the problem; this is the first good explanation I have seen.

It has nothing to do with a clean and oily barrel or cold chamber vs hot chamber. This is a consistent first shot problem when the action isn't loaded by the recoil of the previous shot.

Thanks again for your input.