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303Guy
04-20-2013, 04:41 AM
Got me a new project rifle for paper patch. This one is going to be a challenge. I'm going to have to do some serious fire-lapping on this gun. There is even rust in the chamber - I hope not too deep. That could put a damper on things but I don't have to run at max pressure. If push comes to shove I will open up the chamber and throat and lap that bore larger.

6796967972
67971

But look what came with it;

67970

It's 1942 Mk VII ammo. Not sure why Mk VII ammo would be in a machine gun belt but that's what it is.

Any Cal.
04-20-2013, 04:52 AM
Better you than me, I have a hard enough time with stuff that has rifling...:-)

JeffinNZ
04-20-2013, 05:12 AM
That's not a bore. That's a dry river bed! LOL.

303Guy
04-20-2013, 06:06 AM
Well, I cleaned most of the rust out - using neat dishwasher liquid - and believe it or not, there is rifling under that crud! Good rifling. On the chamber side the rifling lands are actually shiny. There is still some scale so I'll let it soak overnight. The crown is rounded so that will need shortening and redoing.

Dan Cash
04-20-2013, 09:26 AM
I have a #1 Mk III parts junker that is more promising. You are one optomistic son of a gun.

firefly1957
04-20-2013, 09:10 PM
i have a Springfield in 45-70 with a much worse bore and it shoots well.

303Guy
04-21-2013, 05:08 AM
It looks like the first half of the bore is still good, better than the last bit. There is visible scale in patches near the muzzle and visible signs of where scale was. I'm pretty sure the end two inches or so of barrel will have to go. It's not the condition of the muzzle section but that it get's worse near the muzzle. I measured the bore at the muzzle and I get .303 inch. This one could be a j-word shooter.

Anyway, my plans are to fit a charger bridge mounted peep sight with windage and elevation adjustments and some suitable front sight. It'll also get a suppressor.

Any Cal.
04-21-2013, 06:06 PM
Hmmm, integrally supressed, drill holes in the last half of barrel, then you only have the good part of the barrel left.:-) Use a drill and sandpaper to open the rifling for a long paper patch throat, and you could have a little ticker tape parade with every shot! :D

303Guy
04-24-2013, 06:15 PM
We have a public holiday today - ANZAC day - so I checked some older castings for fit in this gun and found just the thing. It's a 207gr boolit for my pig gun but using thinner paper measuring 0.066mm/.0026". This boolit has just the right taper for the throat but is a little small at the base for tight seating in an unsized neck. No problem as the amount of sizing needed is negligible so won't wear out the brass any time soon.

303Guy
04-26-2013, 07:19 PM
Found another boolit for the gun. It's 217gr swaged two-diameter wide meplat.

68563
68575 (I borrowed a different patch)
68564

Did I mention 'wide meplat'?[smilie=1:

It fits the leade/throat like a glove. You can see the brown stain that is the land contact. It contacts with the boolit base flush with the neck base. The paper is the thinnest note pad paper I can find at 0.063mm/.0026" - perfect. It's a tight fit in a fired case too (depending on the make and spring-back). It turns out that the bore is .3028 at the muzzle and is larger at the throat end. (The crown and last few millimetres are pooh).

The nose section core diameter is 7.66mm/.3016" patched up to 7.80mm/.307" which appears to be the bore diameter in front of the leade.


Hmmm, integrally supressed, drill holes in the last half of barrel, then you only have the good part of the barrel left.
I might just do that! Counterbore two inches and drill holes and fit an expansion chamber over it followed by a single baffle, adding a mere 3/4 inch to the length.

303Guy
04-26-2013, 08:14 PM
Fired the boolit.

68571 Base side
68570 Nose side.

It looks smooth because of the catch medium and the fact that it did not expand (much). The powder charge was 20gr W748 with Dacron filler. Penetration was quite adequate, striking the bottom of the steel pot. There are rifling impressions up quite close to the nose and there is no sign of rifling shear - not like this one;

68572

There is no sign of unburned powder and pressure signs on the primer are about non-existent. The firing pin concaving of the primer hasn't even been pushed out (not talking about the firing pin indent - the whole base of the primer gets pushed in).

6857368574

303Guy
04-27-2013, 03:08 AM
I've been having a closer look at that fired boolit. I'm seeing uneven rifling impression on the forward section and while trying to capture what I'm seeing on camera I see something else - the boolit is bent! Not surprising since it's been fired into medium and hit a hard bottom but the apparent bend coincides with the presence on one side and absence on the other side, of rifling impression. OK so I'm not sure, it just looks bent - bucked actually.

Take a look
68601

The opposite side
68602

It is hard to see anything but click on the pictures for a bigger image and see what y'all can see.

303Guy
05-04-2013, 04:06 PM
I gave the bore another overnight soaking with straight dishwasher liquid. It loosened a whole lot more rust leaving grey areas where the rust was in the chamber - I can't see well enough into the bore but a lot of red rust came out. I'm wondering whether a patch of scale has been canting the cases in the chamber causing what appears to be misaligned boolit to bore.

Reverend Al
05-04-2013, 06:06 PM
Just curious ... when you mention "dishwasher detergent" do you mean regular dish soap (for use in the sink) or a particular cleaning product made for automatic dishwashers?

303Guy
05-04-2013, 10:11 PM
Just regular dishwasher liquid detergent. I discovered a long while ago that it was good for freeing up rusted components - pliers were the first use. That was a completely frozen pair. I dropped them into hot water with a lot of dishwasher liquid. It wasn't long before rust discolouration appeared around the hinge pin and I quickly worked it loose. This is the first time I've tried in a gun though. I didn't know that it would work concentrated but it works well.

303Guy
05-12-2013, 04:50 AM
I'm getting despondent with this rifle. I keep getting uneven rifling engraving.

703107031170312

The boolit was a pretty good casting and the patch was OK. Rifling impression goes right to the ogive - the bore-ride section core was just a little under bore diameter but a snug fit in the throat when patched. The boolit seated snugly and was unmoveable by fingers (my fingers). Rifling impression on the bore-ride seems to go up the same amount all round but the impression on one side is deeper than the other, so much so that it's ironed out the gas check rebate and the lube grooves. Can the chamber be off centre by that much?

The load was 20gr W748 with a tuft of Dacron. The primer shows hardly any pressure.

70313

I'm not convinced it's the chamber alignment but I have no way of checking - well, maybe I do using my lathe but it's not something I've checked before. It's difficult enough just setting the bore straight in the lathe (specially when the bore does not run true!) Can one measure chamber misalignment using a chamber cast?

kbstenberg
05-12-2013, 09:15 AM
303 Guy A question from a new PP'er. When the PP bullet is sized to just over bore dia. (.005) Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye? Kevin

Any Cal.
05-12-2013, 08:35 PM
Maybe do a chamber cast of some sort and see what the chamber looks like? Seems like you might be able to see that much difference by eye though.

303Guy
05-13-2013, 01:03 AM
Seems like you might be able to see that much difference by eye though.

Good point, thanks.


Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye?
Mmmm .... Yes I suppose so. I was just assuming that the boolit was contacting the rifling in the throat which I assumed to be tapered. But that last boolit is a .30 bore-ride and my rifle bore is about .301/302 at the muzzle which has suffered more rust damage. Boolits do expand diametrically on firing but this load shouldn't have produced enough pressure to bump up the nose. I wonder? Maybe there's a restriction in the bore. I think I better do some measuring! Thanks for waking me up. I was just sort of noticing the impressions and not thinking further. I'll have to think of an excuse for that. [smilie=1:

303Guy
05-13-2013, 01:07 AM
Seems like you might be able to see that much difference by eye though.

Good point, thanks.


Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye?
Mmmm .... Yes I suppose so. I was just assuming that the boolit was contacting the rifling in the throat which I assumed to be tapered. But that last boolit is a .30 bore-ride and my rifle bore is about .301/302 at the muzzle which has suffered more rust damage. Boolits do expand diametrically on firing but this load shouldn't have produced enough pressure to bump up the nose. I wonder? Maybe there's a restriction in the bore. I think I better do some measuring! Thanks for waking me up. I was just sort of noticing the impressions and not thinking further. I'll have to think of an excuse for that. [smilie=1:

303Guy
05-13-2013, 01:07 AM
Seems like you might be able to see that much difference by eye though.

Good point, thanks.


Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye?
Mmmm .... Yes I suppose so. I was just assuming that the boolit was contacting the rifling in the throat which I assumed to be tapered. But that last boolit is a .30 bore-ride and my rifle bore is about .301/302 at the muzzle which has suffered more rust damage. Boolits do expand diametrically on firing but this load shouldn't have produced enough pressure to bump up the nose. I wonder? Maybe there's a restriction in the bore. I think I better do some measuring! Thanks for waking me up. I was just sort of noticing the impressions and not thinking further. I'll have to think of an excuse for that. [smilie=1:

303Guy
05-13-2013, 01:11 AM
Seems like you might be able to see that much difference by eye though.

Good point, thanks.


Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye?
Mmmm .... Yes I suppose so. I was just assuming that the boolit was contacting the rifling in the throat which I assumed to be tapered. But that last boolit is a .30 bore-ride and my rifle bore is about .301/302 at the muzzle which has suffered more rust damage. Boolits do expand diametrically on firing but this load shouldn't have produced enough pressure to bump up the nose. I wonder? Maybe there's a restriction in the bore. I think I better do some measuring! Thanks for waking me up. I was just sort of noticing the impressions and not thinking further. I'll have to think of an excuse for that. [smilie=1:

303Guy
05-13-2013, 01:28 AM
Seems like you might be able to see that much difference by eye though.

Good point, thanks.


Shouldn't the grove so lightly mark the bullet that the markings from the groves be almost imperceptible to the eye?

Mmmm .... Good question. I was just assuming that the boolit was contacting the rifling in the throat which I assumed to be tapered. But that last boolit is a .30 bore-ride and my rifle bore is about .301/302 at the muzzle. I wonder if there is a restriction in the bore? I'll check it. Of course it is possible that the boolit obturated under sustaine pressure from the relatively small charge of slow (for the charge) powder.