Dual diameter paper patch question

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Bulseyetom
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Dual diameter paper patch question

Post by Bulseyetom » Thu Mar 04, 2021 10:57 pm

So I just got my new to me C Sharps in a 40-70 SS. The barrel is 18 twist with 0.400/0.408 dimensions. The brass that came with the rifle is all Remington 405 shortened to fit the chamber. I fired all of the loaded rounds today (there were about 90) as well as a few of my Hornady 405 brass that is too short for my Hepburn in the same caliber but with a chamber that is 2.58" long. The end result is that it will take a bullet patched to at least 0.411 and 0.412 might be better for a snug finger seat with both brands being about the same. The freebore is 0.300 with virtually no taper. So now the million dollar question, using paper that with two wraps that gives me 0.060, can I go with a bullet that the large diameter will patch to 0.412 without causing some problem that I am not aware of when having to swage down to 0.408 once it starts down the barrel? My feeling is to go with a 0.394/0.405 bullet but am wondering if I would be better served with a 0.406 base diameter. My Hepburn bullet is a 0.396/0.403 bullet to match the barrel and it is too large in the front and to small in the back to work with this barrel. One other question that has we wondering is so many people shoot bullets patched to bore diameter, how do you hold them in the case for hunting applications without severely sizing the brass every time? Thanks. Tom

Bulseyetom
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Re: Dual diameter paper patch question

Post by Bulseyetom » Thu Mar 04, 2021 11:00 pm

Don't know how to edit, two wraps of paper should be 0.006! Tom

bobw
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Re: Dual diameter paper patch question

Post by bobw » Fri Mar 05, 2021 7:02 am

For patch to bore dia bullets. I load the cases with everything but the bullet then set up a 40 SW tungsten sizer die in the press or a 40 Sw taper crimper and just adjust them to squeeze the case enough to hold the patched bullet.
My cases are vld chamfered on the inside just enough to minimize the chance of cutting the patch while finger seating the patched bullet.
bobw

beltfed
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Re: Dual diameter paper patch question

Post by beltfed » Fri Mar 05, 2021 7:43 am

Tom,
You note that the freebore is 0.300'" long.
What is the diameter ? Good info to have to go along with the
fire formed case I.D. to properly set the base band /major diameter
along with the bore diameter part of the bullet to snug, but not too tight fit on the lands.
Should not be a problem with a "squeeze down" of that base band when it hits the 0.408 groove diameter.
Example: in my M1941 MC Sniper rifle/03A1 Springfield, my
best loads use a 0.311 diameter bullet body that squeezes into the 0.308 grooves for X ring accuracy.
Tnis includes gg bullets And PP bullets in that rifle
beltfed/arnie

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Distant Thunder
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Re: Dual diameter paper patch question

Post by Distant Thunder » Fri Mar 05, 2021 8:09 am

Tom,

I am not sure I got this all 100% right?

You are using this rifle for hunting? Hunting loads and target loads are two completely different types when using paper patch bullets.

I am more of a target shooter and my goal is always to get the best accuracy at longer ranges than the typical hunting situation. Hunting usually requires somewhat less accuracy because of the shorter distances being shot. You can therefore bend the rules of accuracy some. Bullet length and fit are more flexible and handling ease and repeat shots become more important in hunting loads.

The chamber in your C. Sharps has a .300" long freebore? If so what diameter is that freebore? It could be more important to fit that diameter than the fireformed cases.

That 18-twist will limit your bullet length some if you're shooting any distance over about 300 yards and accuracy will be best at any range if you keep the bullet to 1.250" or less. I have an 18-twist .40-65 and I have been all over this subject and ended up with a very accurate 2-D pp bullet at the right diameters and length. The free bore in my rifle is .409" dia. and .400" long and I designed the bullet to fit that and the .400" diameter bore. My chamber is cut for R-P brass and a bullet anything over .409" will not fit and still chamber.

You might want to look into some thicker brass depending on your freebore diameter. Ideally your fireformed brass would have the same inside diameter as your freebore.

If you do need to reduce the neck diameter to hold the bullet it is usually only necessary to reduce about the first .125" of the case or less. There are a number of ways to do that and the most important thing from an accuracy stand point is to keep the reduced part concentric to the rest of the case.

I hope that helps. I could be more help if I knew a little more about your chamber. I assume you did a chamber cast? A picture of the cast would answer some questions.
Jim Kluskens
aka Distant Thunder

A new age of tyranny dawns in the United States! If anyone is brave enough to say so they're destroyed by the BIG Tech branch of the Federal Government for spreading lies! "Reeducation" camps to follow!

bruce m
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Re: Dual diameter paper patch question

Post by bruce m » Fri Mar 05, 2021 4:13 pm

arnie and jim nailed it.
bruce.
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Bulseyetom
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Re: Dual diameter paper patch question

Post by Bulseyetom » Fri Mar 05, 2021 4:17 pm

My chamber cast is pictured but not too clear. The bore is 0.400, the groove is 0.408, the freebore area is 0.410 and the inside of the fired brass that I have decided to use is at least 0.411 for a slip fit with 0.412 being tighter. The freebore is 0.300 long. I plan on hunting but also would like to shoot fairly accurate as 99% of the shots will be at the range. I am using Swiss 1.5 duplex loads with Re7. I have cast all of my bullets with 20:1 from Rotometals and think I will stick with that alloy unless somebody convinces me to go to 30:1. I was going to go with a bullet similar to JIM403380E with a flat meplat of 0.250 and the sizes to be determined as to whether to patch to 0.410, 0.411 or 0.412 and the bore patched to 0.398 or 0.399 depending on the advice I receive here. Arnie, thanks for the sample bullets! I was amazed at the length of the taper between the base and the nose. Thanks again to all. Obviously the way to go about it properly is to install a barrel specifically chambered for the brass that you want to use but at my age I cannot justify a new barrel for what few hunts I have in the future. I also fear that the range will shut down someday in the not to distant future as lead bullets are really frowned upon in this great state of California. I cannot even have a lead bullet in possession while in the forest and no hunting of any kind with lead projectiles. Tom
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beltfed
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Re: Dual diameter paper patch question

Post by beltfed » Fri Mar 05, 2021 6:57 pm

Tom,
There is something "strange" about the transition from the freebore to the lands and grooves
is what appears to be a "wavy" "ledge rather than a Leade- a taper from the freebore to the surface of the lands.???
I really wish I could see a better PIC of your chamber case.
Arnie

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Distant Thunder
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Re: Dual diameter paper patch question

Post by Distant Thunder » Fri Mar 05, 2021 7:01 pm

Tom,

Ok, I understood your first post better than I thought.

First you really need to take into consideration that 18-twist barrel! To be optimally stable I would not exceed 1.250" in length (at 1300 fps). Anything longer will give you fits if you have to shoot when the wind is up more a little and especially in quartering headwinds. I've been there and done that. That BACO bullet, JIM403380E, would be fine in a 16-twist, but it's too long for an 18-twist unless you can drive it at 1675 fps or faster. I don't think that would be a good idea even if you could get there with duplex.

I don't duplex and never have with paper patch bullets, but with duplex I'm guessing you can avoid any fouling problems with chambering follow up shots. That would mean you can seat the bullet out a little farther than a typical hunting load, but you'll still want to keep it in the case approximately .200" so you can handle them if the field and not have bullets falling out. You would also be able to patch closer to chamber dimensions without having fouling problems. Again, I don't know any of that for sure, but you most if you've been duplexing paper patch.

The base diameter needs to fit your freebore of .410", so you'll want it to patch no bigger than that or you will likely have chambering problems. If you go with .200" in the case that .410" base would be .500" long before the 3.5* angle starts (.200 + .300 freebore). The remainder of a 1.250" bullet would be .750". If you then subtract the nose length of the JIM403380E which is .724" you end up with a bore diameter length of only .026" and really wouldn't do anything. A shorter nose design of course would increase the bore diameter section.

What I would suggest is that you go with a groove diameter paper patch bullet that patches to fit your .410" freebore as closely as you can. That should give you plenty of alignment. The leading edge of the patch would be up against the leade angle in you chamber and if you concentrically sized your cases to a snug fit on the .410" diameter bullet for the .200" length that the bullet is in the case that would then aide the alignment also.

That is what I do with my C. Sharps .50-70 which also has a .300" long freebore. Those relatively short pp bullets are sized after patching to fit the freebore of my rifle and are in the case far enough to stay well enough for use as hunting loads. Accuracy is excellent doing it this way.

A groove diameter pp bullet simplifies the whole fitting process because you can easily size the bullet after patching to a perfect fit for the freebore.
Jim Kluskens
aka Distant Thunder

A new age of tyranny dawns in the United States! If anyone is brave enough to say so they're destroyed by the BIG Tech branch of the Federal Government for spreading lies! "Reeducation" camps to follow!

bruce m
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Re: Dual diameter paper patch question

Post by bruce m » Fri Mar 05, 2021 11:53 pm

jim is right, just patch to groove, or better, to freebore.
it is interesting to note that of recent times but not most recently this was known as a pp chamber, demonstrating just how much we had lost how it was really done.
bruce.
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Distant Thunder
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Re: Dual diameter paper patch question

Post by Distant Thunder » Sat Mar 06, 2021 8:38 am

bruce,

I maybe just wasn't clear when I said "groove" diameter because as I explained when writing about my .50-70 the bullets are actually SIZED to fit the freebore not the actual groove diameter. In my mind when I say I'm shooting groove diameter bullets it's understood that they are .001 to .002 over actual groove diameter. The same as grease groove bullets would be, groove + a couple.

My understanding is at at least some of the Shiloh rifles before Kirk took over had long freebores, and often tapered freebores, and that has been called a "paper patch" chamber by some.

I have had a few C. Sharps rifles over the past 30 years and all had some amount of freebore, .200 to .300 being common. Unlike the pre-Bryan Shilohs the C. Sharps freebores have been only about .001 over groove diameter and straight. Their main use is to allow any bullet to seat out farther and allow for more powder on the order of what the old balloon head cases held. Thus making a .45-70 a true .45-70 and not just a .45-62.

The barrel of my .40-65 is a replacement and has a Ron Long inspired chamber designed specifically for the RCBS 400 grains flat point bullet to be seated out and give more powder capacity. The problem with that thinking is that bullet is too long for the 18-twist barrel and as such is not a consistent performer.

Once I understood the importance of matching the bullet length to the twist rate that rifle has been consistently accurate. When I designed a paper patch bullet to fit the chamber and match the twist that rifle became my most accurate BPCR.

Those are just a few of the lessons I've learned the hard way over the past 30 years of shooting these types of rifles.

The main point here being, always fit the bullet to the freebore whether it is patched or grooved.
Jim Kluskens
aka Distant Thunder

A new age of tyranny dawns in the United States! If anyone is brave enough to say so they're destroyed by the BIG Tech branch of the Federal Government for spreading lies! "Reeducation" camps to follow!

Bulseyetom
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Re: Dual diameter paper patch question

Post by Bulseyetom » Sat Mar 06, 2021 9:52 am

Gentlemen, lots of good advice. As always, one question leads to another. I have read more than once to use a 9mm taper crimp die to size for a bore riding bullet. Dumb but happy, why the 9mm versus the 40 caliber Lyman die that I use at times to crimp my 40-70 bullets by feel to eliminate the bell so that the loaded round chambers. Jim, my chamber appears to be like you mention about early C Sharps with a straight freebore slightly larger than groove diameter. In theory, if the freebore is 0.410 and the cartridge loaded duplex, should I go with a patched bullet of 0.409 for hunting? Again, thanks to all. Tom :wink:

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Re: Dual diameter paper patch question

Post by Kurt » Sat Mar 06, 2021 10:48 am

I really don't know where or when the cylinder type free bore started. I have looked at a lot of chamber casts of original rifles, Sharps, Maynards, Remingtons and all of those rifles had a funnel type lead from the chamber wall to the lands. Back around the late 70 or maybe 1980 a local shooter had one of Wolfgang Droege Shiloh rifles and I looked down the bore and saw a long double shadow and we talked about the chamber and he ended up making a chamber cast and it had a 45º chamber end transition to a very long free bore to the lead taper. He said it does not shoot a cast bullet worth a darn but it sure shoots the 350 gr jacketed bullets.
Several years later Cabela's came out with the Quigley rifle and I just had to have the Quigley .45-120 and when I got it I seen the long double shadow in the chamber so I made a chamber cast and it also had that very long free bore of .400" and I had a hard time getting it to shoot anyway decent with GG bullets. I ordered a groove diameter PP mould from Tom Ballard and a whole new world opened up with the rifle Pedersoli copied from Wolfgang Shiloh.
If you have a long cylinder free bore chamber shoot a groove diameter PP that fits the freebore snug or if you want the GG you will need a bore riding nose that fits the free bore.
The long funnel type transition is a lube groove or paper patch bullet chamber.
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Distant Thunder
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Re: Dual diameter paper patch question

Post by Distant Thunder » Sat Mar 06, 2021 12:09 pm

Tom,

The unknown for me here is the amount of fouling left in the barrel with your duplex loads. About 25 years ago I was talked into shooting duplex with grease bullets for a few years in my .45-70. It did get me over a hump trying to get enough velocity for 1000 yards shooting with the long gg bullets and not much powder space. It also allowed for a string of shots without having to clean between each shot. What little fouling duplex loads left behind wasn't noticeable with gg bullets. I do not know if it's clean enough for paper patch.

Once I learned how to load black powder and get respectable velocities I dropped the duplex loads and never went back. For long range shooting straight black powder is hard to beat for accuracy. I can understand the use of duplex in hunting loads to get around dealing with the problems of fouling in the field. For target shooting it's very easy to wipe between shot, not so much so for hunting.

I will say that for the best accuracy you would want to patch so that the bullet is a light push into that freebore in your rifle. If there is any amount of fouling in the freebore you would want to patch to a diameter that would allow for that fouling. How much that is I have no idea, but it can't be much.

My target loads all give the best accuracy when the bullet fits ALL the various diameters very close to slightly snug. That includes the case mouth ID, the freebore and the bore (lands). Hunting loads usually have to be somewhat of a compromise because of the fouling.

In my rifles with longish freebores I ALWAYS patch to fit the bore and the freebore snug. Then I use the brass that best fits the base diameter of my bullet and size my brass as little as possible. Most, but not all my target loads have the pp bullets seated very, very shallow. That would NOT be a good choice for hunting loads where deeper seating a benefit for handling. With deeper seating it is important how the bullet fits the brass because you are relying on the alignment the case provides to help with accuracy. With target load 90% or more of the bullet is sitting snug in the bore/freebore when the trigger is pullet and alignment is as perfect as it gets.

You'll have to decide how much if any that you need to allow for the fouling with duplex. I would say that .409" would work, .410" would be more accurate but it has to chamber after the first shot. Starting with a clean barrel and firing one or more duplex loads you would have to try to chamber a .409" and a .410" pp bullet and see what you get. Does it chamber? Is the patch damaged?

Just remember, no matter what diameter(s) the bullet is when you chamber it as soon as you pull the trigger it will expand to fill all available empty space before it moves forward much at all. If there is a lot of empty space in the case, the freebore and/or the bore the bullet must expand to fill it and the bullet changes shape to do so. If there is a lot of shape changing going on accuracy suffers. This is true for cast lead paper patch and grease groove bullets.

Every compromise you make in bullet fit is also a compromise in accuracy potential so make only the compromises you absolutely have to.
Jim Kluskens
aka Distant Thunder

A new age of tyranny dawns in the United States! If anyone is brave enough to say so they're destroyed by the BIG Tech branch of the Federal Government for spreading lies! "Reeducation" camps to follow!

bruce m
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Re: Dual diameter paper patch question

Post by bruce m » Sat Mar 06, 2021 7:37 pm

bubble bubble toil and trouble.
bats wings and sheeps eyes.
slugs and snails and puppy dogs tails.
none of that here in what jim says, as he does not do magic or mysticism when it comes to black powder cartridges.
all that he has said in all recent posts boils down to basic stuff to get right.
without basics you only have luck on your side, and we all know where that can mostly lead.
and the beauty of it all is that it is quite simple to come to grips with.
bruce.
ventum est amicus meus

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