303 Brit ok for PP first timer?

[edwin41]

mabey you could try to start the patch at the first lubegroove and leave the nose bare.
this really worked for me , i also wet a paper disc and stick it at the bulletbase for protection of the bullet .

[303Guy]

Found some of that paper. Measures the same as yours and has a rough side and a slick side. I'm about to test some - not on the range, just in my test tube. I'm going to try my 1896 LE I with an oversize bore - like .307 oversize! Perrrfect for the paper patch and seating in unsized case necks. It needs a tougher paper because the bore is rust damaged but not too badly.

On the church steeple boolit; I notice that the spire point bullets have a better BC than spitzers and am wondering whether a shorter spire would make a good compromise between high BC and long bearing length/short unsupported nose?

[Indio]

On the church steeple boolit; I notice that the spire point bullets have a better BC than spitzers and am wondering whether a shorter spire would make a good compromise between high BC and long bearing length/short unsupported nose?

A shorter but still pointed nose would be better I have been thinking as well, just to make it a bit more robust.. I have been keeping my eye on the pointed NRA PP mold in the group buys, proven 1000yd results and there is talk of offering it to suit .303 Brit as well as the original 30 cal

[Indio]

My range test were not exactly what I had hoped for.. At 25m my 10 shots were spread into about a 1 foot group, 2 of the holes were ovaled. I also had two loaded exactly the same but with the bullets I lubed generously with Alox, the results were two key holes, one a perfect side profile showing a bent nose... I wonder if nose bent in the bore or in flight with some patch stuck to the bullet? This is with a softer alloy I thought I would try first.. Still lots of things to try

[pdawg_shooter]

At jacketed pressures and velocity ANY unsupported lead will slump/distort under acceleration. That is why I lap the bore riding nose section of all my molds to the same diameter as I size the body of the bullet to.

[Indio]

At jacketed pressures and velocity ANY unsupported lead will slump/distort under acceleration. That is why I lap the bore riding nose section of all my molds to the same diameter as I size the body of the bullet to.

My bullets are .305 all the way to the ogive

[303Guy]

303 Brits have a 'shaped' throat which could make fitting a boolit a bit tricky. So that .305 boolit will be a bit loose at the rear which may or may not be a problem. At best it will bump up to fill the throat then all's good or it may cant to one side in the throat then all's lost. Well not all but accuracy sure won't be stellar.

Here's a profile for one of my 303's


It's in SI but it gives the idea. That nose is under bore diameter to patch up to bore - not sure that's a good idea but it's the only way to fit a decent weight boolit in the gun. Actually, the bore-ride section came out with a slight taper which matches the gun. Even more complicated, right? The throats tend to taper past the leade.

[Indio]

I had some time today so I tried making one of the throat impressions with a pure lead slug hammered into a filled case. The distance between the measurements from the case mouth are 0.10in. One of my first loaded rounds is shown just so I could get my head around all of this. I measured the inside dia of the fired cases (full pressure load) from the range test.. 1x .318, 5x .319, 2x .320 .. These were all new Remington cases.

Any tips on what to try next? I have some ideas but advice is always welcome.

[303Guy]

There's that shallow tapered leade I was talking about. The parallel free-bore is interesting. I'd say it's time to load up and go shoot and see what happens. The boolit profile could be changed a little to improve the fit but maybe not necessary. Only range testing can tell. But it does look like the base of the boolit has room to tip sideways if it doesn't obturate immediately on firing (not having comparative boolit measurements, that's just how it looks).

[Indio]

I've ordered some 8mm Mauser expanders that I can reduce in dia slightly so I can play with neck tension with my new cases as I dont have any once fired yet, I'm thinking I want minimal neck tension. My last test was with normal neck sizing and a lee uni expander so I didn't damage the patch on seating, I did have a few tight bolt closes so that needs tweaking.

I looked over my notes and my test bullets are a soft alloy, I'm going to cast some more with the harder alloy I mentioned in my first few posts and some with some cast with linotype a mate gave me. I know people will say I don't want/need hard alloys for PP'ing but I'm going to do the process of elimination thing.. And in my mind I'm hoping there will be a balance point between base obturation and nose sag (the lack of) with the alloy.

Powder charge.. my last test I tried an ever so slightly compressed charge of AR2213SC (H4831SC) with std primers.. There is a bit a bit of info on the net with this powder with the 303 and all the comments are along the lines of its ok with the heaviest bullet but the velocity is a bit slow and you may get unburnt powder.. My results were slightly smoky muzzle blast on firing, no pressure signs on the primer, no unburnt powder in the bore or cases, no smoking of the outside of the case necks, cases are well formed in the chamber. I think starting with the bullet jammed will be helping with the clean burn. I will try this again with my next test but also something faster like AR2208 (Varget) that may help the harder bullets to obturate well (i hope).

[303Guy]

I'd try the harder boolits with the same powder and charge. I did a thread on match alloy strength or hardness to pressure or velocity (not sure). I found a balance which bumped up the mid-section, stopping before the ogive, so theoretically that boolit should shoot straight at that loading. The alloy will deform under stress to the point along the boolit length where the overlying mass is subject less than the yield strength of the alloy. Ideally I think, that point should be close to the ogive so that the whole shank is obturated for best alignment. Anyway, if I can find the link I'll post it.

Found it.
http://castboolits.gunloads.com/show...th-to-Pressure