P14 303 Britsh Groups opening up?

[Muskyhunter1]

I was at the range today and a fellow was shooting a P14 303 British with a 200 grain slug sized to .314 dia GC and was using SR 4759 powder. He started to shoot and had pretty good groups at 50 yards. As he began to warm the barrel the groups opened up.

Is there a Readers Digest version why his groups are opening up. Possible remedies?

Thanks Lads.

[Ben]

Not enough information.

How many rounds fired over what period of time ?

Condition of the bore prior to any shooting ?

How had this particular load done in the past ?

How has the particular rifle behaved with a hot barrel in the past ?

His own shooting skills ? ?

How well does the .314 " dia. bullet fit his particular rifle ?

How much leading was visible in the bore when the shooting ended ?

Could be one or many of a wide variety of variables causing the problem.

Hard to diagnose over the internet.

[Muskyhunter1]

Not enough information.

How many rounds fired over what period of time ?

Condition of the bore prior to any shooting ?

How had this particular load done in the past ?

How has the particular rifle behaved with a hot barrel in the past ?

His own shooting skills ? ?

How well does the .314 " dia. bullet fit his particular rifle ?

How much leading was visible in the bore when the shooting ended ?

Could be one or many of a wide variety of variables causing the problem.

Hard to diagnose over the internet.

I hear you Ben I was just looking for suggestions. I will answer your questions in order.

- He fired about 30 rounds over the period of about an hour. 3 shots walk down range, etc. Not too intense and it was cool - 0 F.

- Bore is dark with deep rifling. He fired some 311 cast and they keyhole at 25 yards. .311 jackets work ok at high speed.

- First time he fired that load.

- He got the rifle from his Dad's estate so no history on its' shooting past,

- The fellow is an awesome shot. He was shooting a 45-70 Browning 78 at 100 yards into almost a one hole group last fall - shooting skill not an issue.

- .314 fit???? That is the question. I am thinking if he needs to go much bigger slugs the rifling might be finished. I suggested he needs to slug the bore.

- Not much leading from what we could see after shooting.

Just looking for some generic suggestions we could look at. Could bedding be a cause of shift with pressure points that are inconsistent? He made his own stock from scratch and did an awesome job.

Thanks,

[Jack Stanley]

The P14 I had needed .316" bullets to run consistantly . Smaller would place the first few in a good group a full magazine would open up .

Jack

[elk hunter]

Another possibility:

Before shooting any old military rifle I try to make sure the bore is as clean as I can get it. Fouling from old military ammo can be very bad for cast bullet accuracy. I forgot that one time and tried some cast in a Krag I had just acquired the first few shots were OK then it sprayed bullets like a hose. It took several days to get it clean, but after that it shot quite well.

[Ben]

Could still have traces ( or most probably quite a bit more than a trace ) of copper in the barrel.

I'm with Jack on this one, I'd like to see it shot with a .316 " dia. cast bullet.

Ben

[iron brigade]

run some 2n1 bore cleaner down the bore and let sit for five minutes. you'll be surprised at how much lead is in that bore. I had the same thing happen a couple weeks ago while shooting my 1903A3. excellent groups for around 30 rounds then they went to pot. bore was clean. or so I thought. put the cleaner in the bore and couldn't believe the leading I was staring at. I was shooting the 311299 sized to .309 with 20 grains of 4759.

[Ben]

Leading isn't always caused by a bullet that is too small, but it is caused by a bullet that is too small in many instances in rifles and handguns.

[Muskyhunter1]

Thanks Lads. I was talking to the fellow yesterday. I will get him to clean it good and try a larger bullet. Will get back to you with results.

[Mark Daiute]

stock rifle with iron sights?