P14 Accuracy Problems

[Anaxes]

I've had a Winchester P14 for several years. It is a nice rifle, mainly matching parts, intact volley sights, overall pretty good condition.

The original barrel was well past its best and I had it replaced by Fulton's of Bisley. I use it for local service rifle competitions, although it has never really shot well. On average it'll keep most shots in the black at 300yds (we're talking a pretty large target/scoring zone).

I took it out this weekend and had trouble just keeping the shots on the target board (300yds). The grouping was very erratic, left and right, high, low, etc. This is with good quality ammunition, the same load the majority of us use for .303 British (Viht N140 -39.5gns, 174gn SMK, Privi cases, standard Remington primers).

This Tuesday I should be able to test it out again, this time at 100yds. Figure it's time for a gunsmith to check it, assuming it still won't group well.

The crown could be better, but it isn't dreadful. This is all I can see that's visibly not as good as it could be. The bolt face is pretty rough - not sure how much impact that would have on accuracy, neither did Fulton's mention it as being an issue when they checked the rifle.

I use the standard iron-sights on it. The front-sight blade is drifted quite heavily to the left.

Maybe it needs a different load? Bullet choice is a bit limited (it's either SMK HPBT 174gn, or Privi in a similar weight). I've never tried adjusting the seating depth of the bullets, just loaded to magazine length.

How well should it group at 300yds with a barrel in very good condition?

This is probably all a bit vague to be of much use, but I don't know enough about them to give a very technical overview of what might be wrong with it. This Tuesday it'll probably be going for a second visit to Fulton's.

Anyway, I'd be interested in hearings peoples opinions on it.

Thanks very much.

Information

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[bigduke6]

The original barrel was well past its best and I had it replaced by Fulton's of Bisley. I use it for local service rifle competitions, although it has never really shot well. On average it'll keep most shots in the black at 300yds (we're talking a pretty large target/scoring zone).

I took it out this weekend and had trouble just keeping the shots on the target board (300yds). The grouping was very erratic, left and right, high, low, etc. This is with good quality ammunition, the same load the majority of us use for .303 British (Viht N140 -39.5gns, 174gn SMK, Privi cases, standard Remington primers).

I doubt its your reloads, I use the same load (but different bullets), I would say its a beding issue if the barrel is good, you mention it has never shot well, was this before or after the barrel change?

[Anaxes]

I doubt its your reloads, I use the same load (but different bullets), I would say its a beding issue if the barrel is good, you mention it has never shot well, was this before or after the barrel change?

Yes, it's certainly load of choice in the UK.

Before the new barrel (original being very worn, including bad crown and seemingly endless fouling) it would keep most shots in the black at 300yds. This is on a '200yd Cadet Tin-Hat Target' - which has a rather large scoring area. It didn't really shoot any better after a new barrel.

The weather was quite poor today and I don't take it outside in the rain. Unfortunately it'll now be Thursday before it is tested.

[bigduke6]

I would guess its the stock bushings or the fore-end, Cant remember the pressure on the barrel but am sure someone will step in, if not do a search (at the top of the page) type in M1917 or P14 bedding, a few old threads should come up.

[NRA]

I have a enfield that just will not group well with boat tail rounds now when I use flat base the thing groups very well. just an idea?

[Bruce_in_Oz]

Is the replacement barrel a "real" original P-14 barrel or a Fultons "custom" job? If an "original" P-14 barrel (Rem, Win, Eddy etc.), is it new, or "pre-loved?

Original barrels made for Mk 7 ammo have fairly deep grooves and rely on the open-based Mk7 bullet expanding a bit to help with the gas seal. If your barrel has previously digested a steady diet of original, cordite fuelled, Mk7 ammo, the throat will be a bit sad.

I would caution anybody thinking of feeding their original P-14 barrel a steady diet of boat-tailed hollow-points. especially if the throat is somewhat less than pristine. Ditto if you are thinking of using up that spare pallet of Mk8Z ball you have stashed in the back room.

Stick with 174-190gn, FLAT based .312" jacketed bullets or consider heavy, cast bullets with gas-checks and moderate loads.

The other BIG problem with "original" P-14s is the rather dubious state of the action bedding, especially if the rifle has been in and out of dodgy armouries for the last seventy years or so. There was a batch that apparently came out of long-term "storage" in one of the Baltic countries a few years back. Miss-matched bolts one can expect, but mismatched barrels? Not that any of the barrels from that batch seem to be good for much except perhaps as heavy-duty tent pegs.

[Brian Dick]

Try the flat base bullets as mentioned above. Boat tails simply won't perform in rifles that have been shot extensively with cordite. If that doesn't improve things, then the stock bearings need to be checked and adjusted.

[Patrick Chadwick]

I took it out this weekend and had trouble just keeping the shots on the target board (300yds). The grouping was very erratic, left and right, high, low, etc... The front-sight blade is drifted quite heavily to the left.

Summarizing the posts so far, and from my own experience with "tired" old service rifles:

Preliminary diagnosis:

1) Your rifle has "deep throat" syndrome.
...1.1)The bullets exist the case before starting to engrave on the lands. The case has some play (otherwise it would not chamber freely) and thus sits on the bottom of the space in the chamber. So the bullet starts out a few thou below the bore axis (center-line).
...1.2) During the free-flight period, before it makes contact with the lands, the off-center bullet allows gas to flow past and erode the throat.
...1.3) Boat-tails are worse than ACWoTAM, they will actually help to erode the throat even more.
...1.4) The off-center bullet is skewed by the asymmetrical gas flow, hits the throat, and is engraved on the skew.
...1.5) The bullet emerges from the muzzle in an unpredictable direction, with enormous groups, maybe missing the traget completely, and very likely with signs of keyholing.

Confirmation of diagnosis:
Measure the maximum cartridge OAL that you could use, regardless of magazine restrictions. A simple and sufficiently precise method has been described several times before in the forums. You will probably discover that the bullet is way out of the case before it touches the lands. Conduct this test with all the different types of .303 bullets you have, especially with the options recommended below. You may well be amazed at the differences. See

https://www.milsurps.com/showthread....ight=Argentino


From which now follows an lengthy extract:
"If you have not already done so, you now need to acquire a length of 1/4"x24tpi (or 6mm x 1) threaded rod with 2 nuts that is long enough to reach from the muzzle right down to the block face when the action is closed, and still leave a bit sticking out of the muzzle for the two nuts. This is going to be used as a simple, but very effective "depth gauge" for checking head clearance (NOT headspace!) and establishing the seating depth and appropriate load for your cartridges. "

So let's find out how to use this home-made depth gauge!

To make it a bit easier, I have gone through some of the steps with one of my own rifles. It is the Boer Mauser, which I selected because a new member on the Mauser forum has a problem that can be narrowed down by using this measurement technique, and I am using a bit of creative laziness and writing all this just once.



Place the rifle on its side on a table. Cock the action (i.e. do not fire it - we do not want the firing pin to protrude)

Insert the threaded rod until it touches the bolt face (block face for the RB)
Run down the first nut until it just touches the muzzle, while keeping the rod in firm contact with the bolt/block face. Use one hand to hold the rod in contact, and run down the nut with the other.

Now, without disturbing the first nut, run down the second nut until it just touches the first. Make a mark with a felt-tipped pen on both nuts.


You have now "zeroed" the depth gauge. I know this is a bit of a 3-hand operation, and I had to use one to take the pics. But with some practice you can develop a feel that lets you measure accurately enough for the present purpose.

Now open the action (remove the bolt) and insert a bullet into the chamber. Use a rod, pencil or whatever to push the bullet into the chamber until it is touching the transition cone - the throat.



This will push the threaded rod back so that the two nuts are now some way from the muzzle.



Now, without disturbing the second nut (further from the muzzle) run up the first nut until it just touches the muzzle again. This requires some practice, as you need to sense when the rod just starts to lift off the tip of the bullet in the throat.

The distance that the nut has moved is the overall cartridge length (OAL) that would be required to have a bullet that just touches the lands before being fired.

Now withdraw the rod some way, so that you can use calipers to measure the distance between the nuts.



Clamp the caliper jaws and use the calipers as a gauge to see how your chosen bullet and cartridge case would match up. The results can be very illuminating!

Firstly, with the Sierra 168 gn boat-tail bullet






As you can see, the base of the boat tail will lose contact before the tip of the bullet engages the lands. That means gas blow-by (leading to throat erosion) and the bullet tipping in the free-flight phase, being rammed into the throat and engraved on the skew, with the result that, even if you have a perfect bore and muzzle, it will go way off course and possibly keyhole.on the target.

Secondly, with the Sierra 140 gn flat-base "spitzer" type bullet.






In this case, although the bullet is considerably lighter and shorter than the HBPT of the same weight, the fuller nose means that it touches the lands while about 1mm is still in the case neck. It will perform better than the boat-tail (which is why I purchased these bullets) but is still barely adequate (which is why I am going to try some that are even longer). The Norma 170 gn Vulkan, Hornady 154 gn or 175 gn Interlock, or Speer 160/175 gn Spitzers or magTips would be possible choices.

For nitro-powders you can back off this theoretical OAL by about 10 thou, and take that as a first-approximation ideal length. (Do NOT try for a much smaller value, or even zero, as bullet and seating tolerances will lead to a maybe/maybe not contact between bullet and throat, leading to unpredictable pressure variations etc).
Of course, in this case it is impossible to get anywhere near the ideal length, as there must be sufficient bullet in the neck of the loaded cartridge (about 1 caliber length) to ensure reliable and consistent seating..."

End of extract

Treatment:
a) Do NOT use boat-tails
b) Use the flat-base 174 gn bullets, if you can get them. The best types are those that have an open base (no jacket on the base) as they will obturate a thou or two more than a fully jacketed bullet.
c) You need the longest cylindrical bullet section you can find. At present this would be the Hornady type 3130, which I have used as a cure for Enfield, Argentine and Russian Mosin Nagant rifles. Check with a dummy round that this bullet does not expand the case neck so much that the cartridge jams. It is not only longer, but also fatter than most, which reduces all the effects listed under 1) above.
d) Seat the bullets as far out as makes sense. There should be at least 1 caliber of bullet length with firm contact in the neck, to provide sufficient neck tension for proper pressure build-up before the bullet leaves the case. The Hornady 3130 has a crimping groove, and you should seat the bullet so that you can just see this groove. Whether or not you crimp the bullet is up to you, I personally just use the tiniest amount of taper crimp.

2) Your rifle has a bedding problem.
...2.1) If the foresight is grotesquely off the center-line, then there is a sideways force acting on the barrel on the opposite side to the blade offset. The barrel is binding somewhere in the barrel channel.
...2.2) Remove the handguard and look. The fore-end may be warped. if the sticking point is not obvious, slide a piece of thick paper under and around the barrel, and move this up and down the barrel channel until you find the sticking point.
...2.3) Removing this sticking point should immediately improve matters. Do not worry about esoteric bedding ideas until you have found and fixed this basic problem.

You can probably conduct all the tests mentioned above in not much more time than it took me to write this post! Please let us all know if the "remote diagnosis" helps.