How much is too much Leade. ?

Discussion of BPCR loading techniques, SAFETY, Case Cleaning and Prep, Indexing, BP Choice, Primers, Wads, Compression, Drop Tubes, Vibration, Load Testing, etc.
Singleshot S.A.
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How much is too much Leade. ?

Post by Singleshot S.A. » Wed Oct 30, 2019 3:47 am

Hi all,
I own a Husky Rolling Block with Douglas barrel in 40/65. It shoots well with a Breech seated Steve Brooks 2 diameter bullet of 400 grains.
I seat the bullet to engrave the second to last band. Reason for this is the breech was cut with over 200 thou of leade or free bore and I have always been concerned about that gap if I seated the bullet in to the Base band. These locally built rifles are about 15 years old and no problems.
Now I have recently sold another 40/65 Douglas which was pretty much a standard breech, and I have two bullet molds that shot exceptionally well in that rifle, but they are traditional Base band molds. Sooo.........
How much is too much gap. ???
Should I use a felt wad to fill part of that gap or do I need to fill the whole gap. ??

Brent
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Re: How much is too much Leade. ?

Post by Brent » Wed Oct 30, 2019 5:56 am

I would seat the bullet until it starts engraving, which it sounds like you are doing with good results. So, I'm not sure what you mean by gap that you would fill with a felt wad? A gap between powder and bullet? I would fill that with a wad, or more likely, more powder (black).

If you have something that works well, why change it?

I guess I am not understanding something.
I'm not from here, I just live here.

Singleshot S.A.
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Re: How much is too much Leade. ?

Post by Singleshot S.A. » Wed Oct 30, 2019 3:46 pm

Hi Brent,
There is quite a gap behind the Breech seated bullet even by seating to the second band. If I try the other bullets and seat to their Base band there will be even more gap. Nearly .200 " 3/16th inch. Is it too much. I am using a full case of drop tubed 1 P Wano with a .030 poly wad. Some shooters talk of filling that gap in front of the case with a felt or cork wad.

TexasMac
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Re: How much is too much Leade. ?

Post by TexasMac » Fri Nov 01, 2019 2:16 pm

So what are the negatives if any of a long freebore when seating the bullet back in the case & having to jump the freebore? I'd like to hear from shooters that have direct experience, not guesses or assumptions. A shooting friend recently acquired a Pedersoli .45-70 Sharps with a lot of freebore. Although a chamber cast has not been made, a visual estimate it it's about 0.250". He shot ammo that was loaded for a Browning .45-70 BPCR which does not have any freebore & did OK but not great at a recent match. I have a lot of experience with a Browning .40-65 BPCR which has a about 0.190" of freebore but I've always loaded with the bullet in contact with the leade or no more than 0.005" off the leade & have not experimented with seating the bullet deeper. The only negative that I can think of when "jumping" a long freebore, assuming the freebore diameter is the same as the groove diameter, is the bullet may not bump up as quickly as when the bullet is in contact with the leade and the chances increase for blowby & gas cutting.

So does anyone have direct experience with jumping the freebore & experimented with various seating depths?

Wayne
NRA Life (President's Council) Member, TSRA Life Member, NSSF Member
Click on http://www.texas-mac.com/index.html to my home page containing information on my Browning/Winchester BPCR book & associated articles.

Kurt
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Re: How much is too much Leade. ?

Post by Kurt » Sat Nov 16, 2019 10:37 am

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When you say freebore, are you referring to a cylinder or a tapered ? there is a difference in the way they perform.
I have rifles with all three different chamber ends, 45 degree, cylinder, and tapered (funnel) plus tapered compound throats.
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Here is a 4 degree/1.5 degree compound throat I put into a Browning BPCR that had a bad factory chamber end and I had a throating reamer made to clean it out.
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This cast is out of my .45-90 90 Shiloh that was changer from a 45 degree to a 5 degree. and there is a great improvement in the performance of that rifle after the change. Most of my rifles I have have the "funnel" type throats.
I'm not quite clear when you say breach seat. It sounds like you still have part of the bullet in the case?? or is it seated with a tool in the above photo ?
I breach seat using the tool above and if you look at the standing case you see the wad flush with the case mouth.
I have seated the bullet so the case makes contact with the bullet base in the long tapered leads and the 45 degree I use in my rifles. And I found no problems with accuracy and looking at undamaged recovered bullets.
I have done extended tests shooting groups alternating shots with the case at the bullet base and with it seated deeper into the throat, but I stopped at 3/16" ahead of the wad with my tests because I get leary of ringing the chamber. I had it happen before do to a hang fire with a bullet seated in the case on top of the wad so I think I pushed the envelope with the 3/16" gap breach seating. I did not see any improvement or worse in the results with the gaps.
Last edited by 2 on Kurt, edited 0 times in total.

Kurt
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Re: How much is too much Leade. ?

Post by Kurt » Sat Nov 16, 2019 10:39 am

I bon't know what happened to the pictures I posted but somehow they got deleted and I re posted them.

Kurt
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Re: How much is too much Leade. ?

Post by Kurt » Sun Nov 17, 2019 9:58 am

Brian If he is doing this I would use caution not to go too deep and I would not use a wad like felt because they are not dense enough.
If the bullet is, say .458/9" and the cylinder freeborn is .460 or plus a little I would not worry about needing extra wads because the bullet would obturate tase enough that it would not cause any gas cuts if there was a good wad stack in the case from what I have looked at.
A PP bore diameter with a fair amount of cylinder freebore .300" plus using a flat based bullet I have seen extensive gas cuts breach seated and with it seated in the case 1/8". Using a cup based bore diameter PP with the twisted tail pressed in the cup pretty much reduces gas cuts I think because of the skirt walls expanding filling the gap. and this also shows on some recovered bullets with the skirts being brighter in color and land cuts and paper grain being deeper.

Singleshot S.A.
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Re: How much is too much Leade. ?

Post by Singleshot S.A. » Tue Nov 19, 2019 7:15 pm

Sorry I haven't checked in recently.
Kurt, I breach seat a 2 diameter bullet which has the last 2 bands at .410, with a tool, untill the lands engrave the second last band of the bullet. . The case is full, with a LDP wad flush with the top. My concern was that if I were to try a different bullet, which is a standard base band only bullet, seated to engrave the base band, I would be adding even more gap between the case mouth and the base of the bullet. That gap would be about .230". That is, the seater is set to protrude .230" from the case mouth.
Anywho.... I have talked to a few others now, who have or have owned one of these rifles and they all are quite happy with their performance, most have never tried a Base band or tapered bullet so were forcing standard parallel sided bullets into the rifling, with pretty fair results.
I have now tried the bullet that I wanted to try, one which shot exceptionally well in another rifle, but alas, it was no better than the one I have now which will do. 👍

Kurt
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Re: How much is too much Leade. ?

Post by Kurt » Tue Nov 19, 2019 8:01 pm

I would advice against a .230" gap between the wad and bullet. It's a disaster possible. It might or might not show up after the first shot but the potential is there.

Keep in mind, when that powder is lit it's a good chance the bullet will be wall to wall in the chamber. But I breach seat a groove diameter in a free bore chamber. That 2 diameter bullet should be a fine way to go to get a positive gas seal in the free bore chamber but keep that bullet against the wad.

My 4 degree funnel throat is long, I haven't done the math but I think it's close to .245" and longer with the 4/1.5 compound and I shoot bore diameter bullets seated in the case 1/8" mostly and I have no gas cut problems with the proper wad stack.

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