Paper patching the .303 British

[beemer]

Could be the pp has more bearing surface and the diameter of the bullet being larger than the jacketed caused the increase in velocity. I tried a .0005” thicker paper and got 30 fps gain in velocity.

I wish I understood that a little better. Seems a PP bullet would offer less resistance than copper would. At the same time powder needs some pressure, as in bullet resistance, to burn properly. I think standard cast and lubed lead give a little more velocity compared to jacketed. Maybe someone has the correct answer.

[Flygrimm]

If you want a cheap hardness tester try the pencil test method:

https://castboolits.gunloads.com/sho...pencils/page13

I bought a Staedtler drawing pencil set for $14 and the results seem to be reliable based on testing pure lead and clip on wheel weights against the chart numbers.

What is you bore diameter"

What is your groove diameter?

What diameter is your cast boolit?

Are you siziing before patching, after patching or at all?

Are you wet patching or dry patching?

As noted, what worked for me was to ensure the cast boolit was at or a little over bore diameter then patch to groove diameter. I did not size. I chose a paper thickness to suit.

For my .308 I used the as cast bullet at 0.301" then patched to groove diameter and that gave quite good results without much work. For the .303 that 0.301" bpplit wasn'[t working even when patched to groove diameter. So I tried knurling to bring the diameter up to 0.303"/0.304" then patched to groove and that worked. This is with ACWW and wet patching.

I have to think a standard .30 cal. bullet at 0.308"/0.309" would need fairly thin paper at 0.0015" to 0.002" thick or if using thicker paper that the patched boolit should be sized to suit the groove diameter after patching. The patched bullet should be at groove diameter ot a thou or so over groove diameter. My guns all run about 0.314" groove diameter as far as I can measure. I size cast GG boolits to 0.315" and that works well.

I didn't know NOE was having problems. I see he has the 0.301" moulds in stock but not the 0.303" moulds. You could knurl the 0.301" boolits up but you need a knurler to do that. Accurate Molds could make you a 0.303" mould but it would be a small FP boolit.

Not sure this is helping you at all!

If you are stuck using a 0.308"/0.309" boolit try patching to groove diameter +0.001"/0.002" or patching larger than groove diameter then size to groove diameter.

Longbow

Let's answer at least a few of these questions.

As to the bore/groove I'm using a new Criterion barrel so I am ASSUMING for now that it's at least close to .303/.311. I know, I shouldn't assume but seen as it's a 4 groove barrel, once I cast the chamber I should be able to easily measure it. More so than a 5 grove.

The boolit as cast is .3085, wet patched with .003" tracing paper and sized to .314 after drying. I'm probably sizing down a little too much from aboout .320 to .314. I'm hesitant to size before patching as I don't want to destroy any surface hardness I may have. Along with moving the patch up the ogive more I might try to find a thinner paper.

I'm going to at least repeat the 26 grain test to see if I can repeat the accuracy results even though the velocity was just shy of 2000 FPS. If that works at least I think I'm on the right track. I'm then going to make up some more projectiles with the paper wrapped higher up to see if that keeps the bore from leading and also to see if accuracy improves as there was some leading in there after my last range trip. Was it there before or after that string we won't know but I'll at least get some more data.

I'm going to give Lyman a ring. They were the ones who made the original molds for Hatcher way back in the day. Maybe they can do something for me. You never know until you ask!

I hate throwing NOE to the back of the bus but 2 years of waiting and I've begun to lose patience.

Will sizing a .3085 boolit down to .304 have any adverse side effects? I've never done that before.

Thanks

Stuart

EDIT: BTW, I'm thinking something in the .002" range for paper might work as the patched/unsized portion of the boolit is around .307, maybe a tad too big. Any idea on which paper might be in that range?

[steveu]

Seth Cole #55w is about .0015" dry and Seth Cole #56 is about .0019" dry. They will get a little smaller, approx.0005", when wet patched is what I have found.

[barrabruce]

I found if I patch to where the paper is slightly smaller than bore diameter on the bullets nose works for me.
It may not be at the orgive.
If I do patch behind where the bore cuts the bullet then I patch to the front of a groove wet wrapped.
When the paper dries it shrinks back into the bottom of the groove and anchors it there.
I then tend to rub the exposed lead with a lube thou.
Works if you have a nice barrel.

[Hamish]

“ Will sizing a .3085 boolit down to .304 have any adverse side effects? I've never done that before.”- Stuart Flygrimm

Stuart, I have sized .325 cast down to .316, .314, and even .310 with no apparent affect on accuracy.

[Flygrimm]

Posted by Longbow

I didn't know NOE was having problems. I see he has the 0.301" moulds in stock but not the 0.303" moulds. You could knurl the 0.301" boolits up but you need a knurler to do that. Accurate Molds could make you a 0.303" mould but it would be a small FP boolit.

I didn’t realize NOE had the 30 cal PP mold in stock. I just ordered one with a Lyman style top punch. I want to try PP in my 1903 Springfield as well. Maybe try a slightly thicker paper and see how it works in the 303 as well.

Posted by Hamish

Stuart, I have sized .325 cast down to .316, .314, and even .310 with no apparent affect on accuracy.

I might try this with my current Lee boolit to see if I get a better fit after patching.

Stuart