Designing the 2-diameter paper patch bullet.

[J.B.]

Finally tried my dual-diam, .44 bullet from Steve Brooks and as expected 'all bets were off' beyond about 500 yds. I had it made fairly long at 1.446" for a 1/17" twist rifle so it wasnt a big surprise in my 1/19. Have now dropped it back to 1.346 to better suit the slower twist and hope to give it a run later this month. No paper-target shoots scheduled until next year now so I'll have to make do with steel. Fingers crossed it cools off a bit and/or we get some rain or the shoot will get cancelled .

Gavin.

[Distant Thunder]

Gavin,

Length and shape are just as important to be matched to your twist rate whether paper patch or grease groove. I spent more time thinking over the length to go with in my 18-twist .40-65 than any other detail when I went to a 2-diameter ppb for that rifle. Being it was going to be used for silhouette I wanted as much weight as I could get in a relatively short .40 caliber bullet, that meant a round nose bullet. From my experience round nose bullets are more likely to stay well stabilized when working at the upper end of the length for a given twist. So I felt fairly confident at the 1.250" length I went with even though I have been deliberately staying on the shorter side with my bullets and it has been working well. Weight isn't more important than stability especially as the range gets extended.

So far that bullet has been everything I hoped for and a bit more. I'm looking forward to shooting matches with it again next year.

Sure wish I could send you a little of the cold rain we've been having here of late, I've about had all I care for that much I know!

[J.B.]

Thanks Jim. As you say, the 'old faithful' ( dare I say it ? ) 'Sharps style' round nose bullet still seems to be the most forgiving... or it has been for me at least. I havent quite mastered rolling the patch neatly over a flat base so I went with a shallow cup base. This of course took away a little weight for a given length. At 1.446" in 16/1 its coming out just over 520 grains. I've been able to twist the base into the cup without a big tail or protrusion and the paper is cuttng loose nicely at the muzzle. Not the preferred method these days apparently but its working for me at the moment. Time and opportunity to test is more of a problem. Test at one match in preparation for the next match I'm sure I'm not the only one in that boat though Those blocks look magic & I'll be interested in your feedback when you get a chance.

Gavin.

[Kurt]

I find nose shape and the ratio between the length of the ogive compared to the shank is a fine balance point of stability for all wind conditions and most forgiving with the ROT. A bullet nose like the original Sharps, Gibbs, Maynard or Metford type nose will handle bullet length better in a wider range of twist that a sharper pointed bullet has.

[J.B.]

G'day Kurt. In complete agreement with you there. Those Sharps style bullets were working better at Big Hill in my rifle than the ammunition I'd loaded myself. Thats why I'm back home re-inventing the wheel.

Gavin.

[Kurt]

Gavin just make sure the wheel you invent is round
Snow is getting close

[Distant Thunder]

Kurt,

I've been making the nose/shank length at about 50/50 with the nose being a little bit shorter at times but never longer than the shank. I would not do that with a more pointed nose shape, but my version is blunted with a 1/3 caliber radius. There are those that don't agree with me on that but it sure works well in my rifles. I believe the center of gravity location is very important to long range stability and the nose radius helps move the CG forward. I like to have an overall length of 1.430" to 1.440" for my .45 calibers with 18-twist. I make the nose .700" to .720" long. Those are the dimensions I have had the most success with. At least those are the dimensions before the big bang!

Last year I took the bullet I had used with only a some success and shortened it from 1.460" to 1.440". That little difference has made a world of difference in the last 3 long range matches at Lodi this year. I am amazed that little difference in length would take a bullet that had been an ok shooter and transform it into a match winning bullet, but I didn't change anything else.

I have only changed two things in the past two years, the bullet length was shortened to 1.440" and I started seating a little shallower at about .090" in the case.

I should try to recover a few of my .40s and .45s this winter and see what I'm actually sending down range. Whatever they look like they are working.

[Kurt]

Jim,

I like the design of your bullet. I personally would not go with a nose radius smaller for a .40-65 if your planning to use it for past 600 yards. That nose you have will do a fine job. I think if you put some of those with 1/16 alloy and not softer then 1/18 with a smidge of poison antimony in the snow and look at them when you find them I don't think you will be disappointed.
I saw something last winter that was a real eye opener for me. I tested the 14 twist .40-65 with different alloys as well the .45-90 with the same alloy and I always figured the .45's would get more nose setback then the lighter .40's but not so. The .40-65 had the nose setback more with 60 gr of 1.5 Swiss then the .45-90 that had 83 gr of 1.5 Swiss shot at the same time in the same pile.

I have elliptical .40's and prolate 40's and they don't hold up as well as the original bullet design of the original like the one in the .44-77 below. That design will hold up as far as your sights will allow you to shoot the rifle.

Kurt

   

[Distant Thunder]

Kurt,

That .44 bullet is essentially the same shape as my little .40 ppb. My bullet has held up very well out to 600 yards and held its own against the .45 calibers. It does require more come up than the higher BC .40s like Arnie Seitz and Bob Wood are shooting, but the accuracy has been good all the way out to 600.

If I went to Arnie's elliptical design at a length for an 18-twist I don't think it would weigh even 350 grains. I want all the weight I can get for the rams. I'm pretty happy with it as is.

The one on the left is Arnie's elliptical and the two on the right are mine, unpatched and patched.

[Kurt]

Jim I don't know which .40 Arnie used at the last Lodi him and I shot together the .40-65 or the .40-72 when he shot the 99 on the 800 but I think he used that bullet and he gave me some but at the 900 and the 1000 he had a lot that cut oval holes so I think they were at their limit with the load he was using.