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View Full Version : Paper patching for 7.7 Japanese



rayg
08-15-2009, 03:48 PM
Japanese rifles have Metford rifling and the rifling is not deep or sharp and
I have been trying cast bullets in my Japanese rifles for awhile trying to get them to work well but they never did group real well and there were always flyers. I tried hardness from bhn 14 up to 22, beagled, unbeagled, over sized, undersized bullets etc. Nothing seems to work well.
I then thought that maybe the paper of a paper patch bullet might grip that Metford rifling better then lead as jacketed bullets work ok so why not the PP'd ones.
Anyway I sized some 314299 bullets to .312 added two wraps and sized them to .319. The groove on my T-99 Long measures .317+. I loaded them with 38 grs of I-3031 powder in un-neck sized fired cases and went to the range. I only fired ten rds at 35 yrs, but the groups were decent and no flyers. Probably about as good as my Jacketed reloads and my old eyes are capably of.

But I want to try some reduced loads. With my other rifles, Enfields, Mausers, and 1903's I use mild plinking loads of 10 grs Unique, or 16grs of 2400 with the cast bullets.
And I was wondering if a light load would also work with the PP bullets. I'm going to be loading up some to try. Can anyone tell me what powder they think would work better for a light PP load, a fast or slower burning powder? The powders I have are 2400, I-4227, I-4198, Unique, I-3031, I-4798.
I'm open to any suggestions. Ray

303Guy
08-15-2009, 05:32 PM
I think the trick with reduced paper patch loads is to ensure the patch disintegrates at the muzzle. I do my patching tests in a 'test tube' using mostly 4227 (and before that lil'Gun that contaminated with 'Varget'). Some patches don't 'shred'.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-040F.jpg
http://i388.photobucket.com/albums/oo327/303Guy/MVC-033F.jpg
http://i388.photobucket.com/albums/oo327/303Guy/MVC-064F.jpg

Those are tracing paper which I believe is 'Vellum' - 100% cotton. Damn strong when wet! That last one stayed on the boolit and got 'peeled' off in the catch medium.

I would suggest that you go right ahead and try the medium pistol powders you have and work your loads up until the patch breakes up and separates properly. Starting off with an over-groove size boolit may well help. I did get lined paper to come off quite nicely. I have not done any range testing of these reduced loads so cannot say that they will actually work but folks have reported having success with pistol and revolver patched loads, so.... :roll: What might be the trick is to get sufficient pressure at some early point in the bore to fully 'obturate' the boolit - that is to say, apply suffient lateral pressure between bore and boolit to cause the patch to break up.

Another 'reduced' load powder to consider is a faster rifle powder to give around 1600fps or maybe more. I was shoting 225gr plain cast with G/C to around 1900fps and this was real comfortable recoil wise. Sweet shooting.

runfiverun
08-15-2009, 05:55 PM
28 grs of the 4895 should be right around 1900 fps.
right in the window for good velocity/accuracy [plain cast] if you see vertical stringing use a filler.
i have had some good [real good]success with a loverign design in the 7.7
but get spectacular two shot groups with some pp boolits, great for hunting.

1874Sharps
08-15-2009, 06:35 PM
Rayg,

You may try a load of 13 to 15 grains of IMR 4227. That load has worked for me fairly well in the 303 Brit for a moderate load and ought to work for the 7.7 as well. Good luck with it and let us know how you do!

rayg
08-16-2009, 11:47 AM
Rayg,

You may try a load of 13 to 15 grains of IMR 4227. That load has worked for me fairly well in the 303 Brit for a moderate load and ought to work for the 7.7 as well. Good luck with it and let us know how you do!

Are those loads for cast or papered?

303Guy
08-16-2009, 02:50 PM
FWIW, 12.5gr H4227 behind this Lee 185 grainer was enough to shred the patch off at the muzzle and that was a 'vellum' patch, so I would guess that 15gr 4227 and lined note-pad paper would work just fine as a light load for plain cast or patched. I don't recover any large pieces when testing lined paper at 15grs.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-032F-1.jpg

When testing lined paper for 'separation', I layd a clean cloth right accross the 'test tube' and found the fragments scattered away from the bullet hole but there is also a considerable gas blast (which probably carries the fragments onto the catch cloth).

This is the 'test tube'.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-558F_edited-1.jpg

1874Sharps
08-16-2009, 03:23 PM
303Guy,

That is a cool "test tube" that you have devised. I think I just might rig up something like that to catch my patches when I go out to the range next time. This is a great forum to share and learn stuff!

303Guy
08-16-2009, 04:17 PM
It is indeed a great forum to share and learn.

This is what's inside the 'test tube'.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-556F_edited-1.jpg
Well, it's changed a bit now but the idea is the same.

fiatmom
08-29-2009, 10:07 PM
How does one make a test tube? What media catches the bullet?

303Guy
08-30-2009, 06:37 AM
I use damp rags. There is a steel (4140) pot of wet sand at the bottom.

I'll find some pics to show how I did it.

pdawg_shooter
08-31-2009, 08:23 AM
I have never had much luck with reduced loads and paper patching. If I were to shoot reduced load I would just lube and load, I think.

303Guy
08-31-2009, 03:27 PM
I have never had much luck with reduced loads and paper patching.I use reduced loads with patched boolits to see how the patch and casting is behaving in the bore. I have been able to determine that softer castings do obturate. Also, light loads tell me if the patch is entering the bore without damage. From what I have heard, I would not bother to range test a reduced patched load. Besides, I already have what seems to be a perfectly good plain cast boolit for reduced loads.

RMulhern
08-31-2009, 03:54 PM
303Guy

Here's a project for you! This comes from Franklin W. Mann's book "The Bullet's Flight".

Make a box of wood around 15' in length. Fill it with sawdust saturated with machine oil. The correct method of preparing is to sift through a No. 12 mesh sieve fine maple or birch sawdust and mix with thin weight machine oil which will not gum. The dust takes much oil, and sufficient must be added to thoroughly saturate without dripping; then resift through a No. 6 or 4 mesh, and if properly prepared it will not cake but will fall back into the furrow made by a bullet!

Photos within his book show bullets recovered in pristine condition and undoubtedly he recovered thousands of bullets using this procedure/method!!

303Guy
09-01-2009, 05:15 PM
Thanks FMPIII. That is exactly what I need to do! Mmmm .... one day .... Something to plan for.:roll:
I'll keep a copy of your post as a reminder.

I had a plan to build a silencer box to fire through into some sort of closed steel catch box but had no idea of a suitable catch medium. I actually already have two of the catch box sides! Mmmm....

rayg
09-07-2009, 10:52 AM
The reason I am looking to light PP bullets and not plain light load lead bullets in the 7.7 is that none of the cast bullets loads I tried had worked well with the Medford rifling used in the Japanese rifling.
A couple of weeks ago, I loaded up three batches of six rds each with light paper patched bullets using the following loads.
20 grs I-4227
21 grs I-4198
16 grs 2400
All paper seperated from the bullet out the muzzle.
I only shot at a 35 yr target. The groups were not impressive but there were no flyers which I always had with plain cast loads
The best group was the I- 4227 , 20 gr load at about 2-1/2". I think, because there were no flyers, the paper seems to be gripping the shallow metford rifing better and I will try different loads to try to close up the groups. Ray

303Guy
09-07-2009, 03:36 PM
rayg

Do you have to shoot light loads? I did most of my patch testing with light loads so I could see what was going on in my trap. I had difficulty getting the patch to come off evenly and in small pieces. That's why I ask. You might try 'weaker' paper for light loads. The other thing that helps is an oversize boolit - one that only just fits the throat. Using a powder and charge with sufficient initial pressure to 'bump up' the boolit might work too. (I am not a fan of loads than can be destructive if accidently double charge or go over the top if erroneously increased).

Did you use a filler in your test loads? Some folks seem to get better results with cotton wool filler but cotton can scourch and burn, causing field fires! Success is often reported with other fillers. Wool filler is an option. I like cotton because of its apparent bore cleaning action and seems to protect the boolit base. No doubt other fillers also protect the boolit base. But I think that cotton compacts behind the boolit to form a wad. I don't know.

Something else you could try (I have not tried it). Dry wrap your patch - that requires twisting on your fingers to get it tight) ans let the patch 'overhang' the ogive some. The idea is that as the boolit leaves the muzzle and hits the stationary air, the 'overhang' acts like a scoop, causing the patch to get 'blasted' off. This might only work at higher speeds and might not work at all! But then again, it might just work.[smilie=1:

Just some thoughts.

rayg
09-07-2009, 11:12 PM
I'm just interested in light loads which are easier on the shoulder and of course conserve on powder. It dosen't matter if the loads are heavy or light. Cast bullets just don't work well in the Metford rifling.
I tried COW filler one time and it did'nt matter, the cast bullets fail to grip the shallow rifling well. I tried both 23 bhm and 14 bhm hard bullets and they didn't make a difference. I think the PP bullets are going to do the trick though.

Enfields have various size bores and many have oversize bores. As an example, Here are the sizes of my four Enfields. All different.

No.4 MK I 1944 BSA "T" sniper, bore .305/ grove .314, 4 grove
No. 4 MK I 1931 Enfield Trials "T" sniper, bore .304/grove .314, 4 grove
No. 4 MK I 1942 Maltby mint/unfired, bore .302/grove .3165 , 2 grove
No. 1 Mk III 1916 BSA, bore .306/grove .314, 5 grove

303Guy
09-08-2009, 12:17 AM
Does your two-groove have very narrow grooves? Mine does and it causes a problem with cast or patched boolits because there is so much displacement of material that the boolit base gets distorted. A rebated (GC boolit without the GC) or semi-boat tail boolit would likely work if the rifling doesn't shear the lead.

rayg
09-08-2009, 10:45 AM
The gooves look to be the narrow ones.
I don't intend to shoot it anyway as I just got it out of the woodwork and it is in mint condition and appears to be unfired since proofing. Cosmoline was in the action and bore. The rifle had been stored in a heated garage for many years and it just had a fine film of storage grime on it when I got it which when cleaned off displayed a 100% new looking rifle. No import marks at all as required by US including the "tons and England stamps. Ray

I just realized the Enfield related info was supposed to be posted on another thead, sorry about that. Darned if I can remember now what one it was supposed to be on though. It was something about a guy with a No. 5 Enfield carbine having accuracy problems, Ray

rayg
09-10-2009, 08:57 AM
Well no luck at the 50 yrd range with three different loads with the PP bullets
5 rds w/ 38 grs I-3031 powder. large 4-1/2" group
4 rds w/ 38 grs I-4895 powder. A little better, just under 4", but still not good.
5 rds w/ 20grs I-4227 powder. about the best but still about 3" group

Back to the drawing board. I thought the 3031 powder would work well as it seemed to show potential at the 35 yrd with the only three rds I had to shoot with that load.

I will try diffent powder levels next, maybe I need to find the right charge. I think I will try reducing the loads next. Also I will try a different bullet. I've been shooting a 314299 bullet sized to .312 and double wrapped and sized to .3185. The groves mike to .3175. Next I will try the lighter 311413 bullet. It could be the 200 gr bullet is to heavy for the 10.5 twist of the rifling. Ray