M1 Grouping Problem

[pdh]

Hello Gents....

Was at the range today to group my M1 at 100 yds. Out of the 3 clips...the first shot out....of each clip....was a wide flyer..low to the left.

What is causing this...shift of the action in the stock?

Everything is tight on my rifle....gas cylinder....the gas lock..

My the rifle has been accurized for the John C Garand Matches several years ago and this is the first time I am getting flyers like this.....

 

[DaveInFloweryBranchGA]

Your rifle may need to go in for a tune up.

Regards,

Dave

 

[pdh]

That's what I thought.......

 

[hps1]

Check to see that there is a few thousandths of an inch clearance between your gas cylinder and the upper handguard. If there is no clearance, as the barrel heats, pressure can cause shift in POI.

Regards,
hps

 

[dmftoy1]

+1 on what HPS1 said.

Before I put a little clearance in mine it would shoot incredibly tight groups for the first 3 and then start vertically stringing and I'd have to put in an extra click for every stage. I had an old timer point it out to me and after following his advice and sanding a little bit off the problem went away. Gettting that spring clip off can be tricky though so make sure you've got the tools or an old timer around so you don't split your handguard!

 

[pdh]

Thanks for the replies gentlemen..

 

[10X]

If it is the first round of each clip, are you letting the bolt slam home on the first round or are you easing it home? The bolt has to be in the same place each time to have consistent accuracy. Easing the bolt forward does not match what the rifle does on it own with later rounds. I have had this happen to me too, but not that much of a flier.

 

[1KPerDay]

You can check if its a heat issue by firing 2 (or more) clips one right after the other. If you still get first-round flyers... look elsewhere for the problem.

 

[cracked butt]

If it is the first round of each clip, are you letting the bolt slam home on the first round or are you easing it home? The bolt has to be in the same place each time to have consistent accuracy. Easing the bolt forward does not match what the rifle does on it own with later rounds. I have had this happen to me too, but not that much of a flier.

That was my first thought as well. Try bumping the back of the charging handle with the heel of your hand after chambering the first round to make sure the bolt is locked all the way shut.

It doesn't look like a bedding/heat issue where the shots would be stung out- the last 7 shots of the clips are grouping very nicely.

 

[pdh]

Yep ...in loading...I bump the charging handle with the heel of hand and let the bolt slam into battery.

I let the rifle set first around 10 minutes or so before the shot each clip....

Looking at the rifle in regards when I first got it.....nothing has changed as far as the gas cylinder touching handguard. I can take photo of it and let you guys take a look at it....

One thing...I store the rifle with the trigger group unlatched...and lately...it takes alot more pressure than it used to...to latch the trigger group....for some reason

Man...this is puzzling...there is an M1 doctor acouple of hours from me..but...um..I don't know....

 

[10X]

If you are storing the rifle with the trigger group unlatched, I can understand the first round of the first clip being a flier due to the action resetting in the stock from recoil. Especially true if it is getting harder to latch the trigger group, the wood is swelling.

I glass bed my rifles and leave the trigger group latched. Zero doesn't change.

I do not understand the first round of subsequent clips being fliers, if you are letting the bolt slam home after loading. The bolt is the only variable with the first round of any clip that I have found affects zero.

 

[hps1]

It is common practice to store accurized M1's w/trigger guard unlatched to keep from compressing stock and/or lose tension on the trigger guard. I have always done so on my M1's and it does not affect accuracy of first or any subsequent round.

Regards,
hps

 

[pdh]

Next range outing......will try loading single shot and see if there is a difference.....Wonder if there could be something about the clips in the way that I'm loading????????

 

[MythBuster]

http://www.eotacforum.com/viewtopic.php?f=109&t=26735

 

[pdh]

I said I would show a few pics of my M1....As was brought up....there is no gap between the gas cylinder and handguard.....

As you can see....she isn't junk.......

I e-mailed the fellow that worked on it for me several years ago......see what he says....sure hate to sent her out FedX or UPS ..............

Thanks again for all the replies and help...they are all well noted.....

 

[chauncey]

this is a dumb question - but is your front sight firmly in place?

I fell prey to this, once, cost me 1/2 a bandolier trying to figure out what the heck was going on...

 

[hps1]

As was brought up....there is no gap between the gas cylinder and handguard.....

May or may not have anything to do with your problem, but, any pressure on your hand guards can affect accuracy as the barrel warms up. The gas cylinder should not touch the upper (front) handguard and the lower handguard should have just a few thousandths of an inch clearance between the receiver as shown in following pictures.

My lower handguard is epoxied to the barrel flange and the upper handguard is screwed and epoxied to the flange. Not a "field" rifle, but helps accuracy. Not sure if legal in current Garand matches, but was legal in the CMP leg matches.

Also note the bevel ground on the lug at bottom of gas cylinder (seen just below the stacking swivel) to assure no contact w/upper handguard in following picture:



One other modification to the gas cylinder is to open up the rear band a few thousandths so that it does not contact the barrel at all.

The NRA used to put out a publication on accurizing the M1; don't know if it is still available or not, but I have accurized six or eight CMP rifles using these instructions and all shot close to moa w/good ammo.

Keep us posted as to your findings on your rifle.

Regards,
hps

 

[hps1]

Couldn't get this picture to show up in above post showing clearance between the receiver and lower hand guard:



Regards,
hps

 

[NC-Mike]

I'm voting for the trigger guard being opened and hence that flier.

What happened between the time you bought it and now? You probably fired lots of rounds and now the action has some play. The first shoot slams the action back into the stock and tight groups ensue.

Next time leave the trigger guard closed and see if you get that flier again. If you don't, a bedding or re-bedding might be the answer.

 

[pdh]

Yes...everything up front on the rifle is tight....

 

[30Cal]

Looks to me like a classic case of first-round-flier. Take it to the smith and see if he can work it out; otherwise, compensate.

 

[pdh]

Gents.....sent the fellow....that built my rifle....an e-mail and the target pics. He said he could not know anything mechanically in the rifle that would cause the first round flyers like these.

He told me to run some tests......Shot from 100yds. Now...I went down to the 155gr bullet with IMR4895 powder.

1) Fire four shots...load single...with each shot...rifle out of sandbags between each shot.
2) Fire four shots...load single...keeping rifle in same position in sand bags
3) Fire just the first shot out of four different loaded clips..
4) Load clip with 4 rounds and fire....

Finally....shot a full clip...with the 168gr bullet...had that same dang gum flyer on the first round...

1)

2)

3)

4)

Full clip...168gr bullet.....



Ah...probably just need shooting lessons. The targets...also...are the birchwood casey...shoot..N..C. 8 inch black. Maybe need bigger black for 100yds.

Anyway....just thought I would pass this stuff on....