PP Problem: That Nasty Paper Ring

[Jack Bickley]

Howdy,
I've been pretty much a silent observer sitting back and listening to all the comments from those who shoot PP bullets. I've learned a lot from the tips you more experienced guys so willingly share.
I've got my load to a point where I could shoot all day long with no wiping, no blowing, if it wasn't for a paper ring that gets left in the chamber every three or four shots. I am shooting a 45-90, with Starline brass measuring 2.397, annealed, in my Shiloh.
Here's my load. Don't shoot me now. This is the only way I've found to keep away from a fowled bore. I start with 4.0 grns. of Reloader 7. Then 84.0 grns of 2F Goex, a waxpaper wad (the ring is not the waxpaper wad. I get it with or without), 3/16 SPG cookie, a .060 fiber wad, then a 505 grn. .443 dia. swaged straight sided bullet with a cupped base, wrapped with Fidelity 9lb. Onion skin, 25% cotton, bringing it to a .450 bore dia.. Its seated in the brass about 3/16" and taper crimped. The paper is put on dry and shot dry. Compression is about 3/16". My groups are about 2 1/2" at 100 yds. Thats about the best I can do nowdays.
How do I get rid of that paper ring. Sometimes when I remove the empty its right on the end of brass. I know its coming from the PP, but why? Would it help to seat the bullet out further? Less crimp? I can spin the bullets in the case after crimping them as it is.
Any pointers would be greatly appreciated:?
I'm soooo close!


Thanks,
Jack

[Brant Selb]

Jack

Don't feel too guilty about the duplex load, I know someone who does that occassionally. Your paper ring is caused by the space between the end of your case mouth and the beginning of your chamber; upon firing, the bullet is expanding and the paper is being forced into the gap at the end of the case and is being sheared off forming the "ring"---sometimes it will stick to the case mouth and others it will fall into the chamber. The longest case length you can use and still clearance the end of the chamber will cure the problem as will a slower powder and seating the bullet out further. In my opinion, the key is the case length.

Brant

[Brent]

I agree with Brant, but a partial remedy is to put the bullet further out there. That is seat less of the bullet in the bore. Try about 0.1" or so.

If you wipe between shots you can loose that smokeless.

Brent

[Orville]

The crimping is also damaging the paper at the edge of the brass, go to a neck sizer, and as others suggested, longer brass, and slower powder will slow the upset of the bullet.
Using a thick walled brass trimmed to with in .005 of the chamber end will make it work even better.

[Digital Dan]

Not arguing against what's already been said, it's undoubtedly correct...but,

The paper is put on dry and shot dry.

Have you tried lubing the patch after it's wrapped? There's little I know about this art and BP, but dry patches will polish a bore right quick...used that trick to take the gray out of a dark bore on a .405 Win. I assume it has abrasive properties when not lubed. Dunno if it would help with the paper ring problem though.

[bobw]

Well JB nobody said it but sounds like you commited the cardinal sin of trimming the brass to short for the real chamber length instead of how long (2.4") you thought it was. Hmm maybe time for some heavy loads to stretch the brass back out some or get some new and leave the trimmer alone until you find your ACTUAL chamber length. bobw

[Jack Bickley]

Thanks all for your ideas.
I think I'll try seating the bullet shallower in the brass first. Then mabe some IMR 3031 in place of the Reloader 7.
I know I could drop the smokeless and wipe every shot, but I'm trying to get away from wiping.
I did not commit the cardinal sin of trimming my brass. They are unfired and all I did is anneal them. They are 2.397.
Seeing as how you mentioned it, I just measured my once fired emptys and they measure 2.399. Mabe after I fire them a couple times they will stretch.

Thanks again,
Jack

[boge]

It's not the brass IMO, it's the crimp. If you don't like to wipe you're in the wrong sport.

[Jack Bickley]

boge,
I can shoot all day long with my Paul Jones grease groove bullet with pure 2F Goex and never wipe or use a blow tube and nail the gong at 220 yards every time. The guys with the fancy sniper rifles stop shooting and watch in amazement.
I'm just trying to find a way to shoot PP bullets the same way.
Its not that I mind wiping, as long as when I'm wiping I'm done shooting.

Thanks,
Jack

[boge]

Using smokeless powder to duplex BP loads is analagous to putting a JATO on the back of a mule.

[LH]

putting a JATO on the back of a mule

It "would" get the mule moving though

[Crash Landing]

Jack
Brant, Brent, and Orville are all on the right track as to what is causing your paper ring in the chamber or stuck to the case mouth. The only other element that needs to be considered is brass cartridge mouth wall thickness. Today’s BPCRs are mostly chambered for groove diameter, or over, bullets. Your bore diameter paper patched bullet has its base bumped up to fill the chamber as the powder ignites. As the bullet moves into the throat, it is swaged back down to groove diameter, shearing off that pesky little paper ring from the bullet base. You can clearly see this if you recover fired patches lying on the ground immediately to the front of your firing position. The portion of the patch that was folded over the bullet base will be separate from the remainder of the patch pieces. A partial cure is to have the case length match your chamber length but unless you address the oversize chamber issue, the problem is likely to persist. You can try to cut down some 45-2.6 or longer brass to fit your chamber and thereby have brass with a thicker case mouth and in some rifles this works. The only sure cure is to buy custom brass as made by RMC (and probably others) with thick case mouth walls to match your chamber. Orville wrote an excellent post some time back that goes into detail on how he addressed this issue for a 40-90. The measurements are easy to figure out once you get a chamber cast and RMC has a more-or-less standard thick mouth that will probably work for your rifle. The thicker case mouth wall will not allow the bullet base to bump up over groove diameter so it will not have the swage back down as it enters the throat.
Hope this helps

[Jack Bickley]

Crash Landing,
I have retrieved the shredded paper and have found exactly what you described. It matches the paper folded under the bullet.
I think it showed up about the time I increased the amount of BP in my load and started to compress more. That was prior to trying Reloader 7.
I had been wiping between each shot then, so it didn't hinder chambering the next round. The paper wiped out each time.
I loaded 15 more test cartridges with the bullet seated at .120, which allows the same amount of BP, but which means less compression. I also reduced the Reloader 7 . I'll see how that works out.
Thanks everyone for your valued expertise and discriptive analysis. I'll keep you posted on my progress.

Thanks,
Jack

[Timberlake]

CrashLanding,

I would take issue on your post about the base portion of the patch being sheared off and left in front of the muzzle, and the reason(s) why.

Every single round of pp bullets I fire shows this base material in front of the muzzle. I feel it is from the wad staying with the bullet a few milleseconds after exiting the bore. In other words, the outer paper shears off and the base material stays those few milleseconds because of the base wad. It is probably attached until it exits the bore. I don't feel it is from the case/chamber length relationship.

These paper shreddings are no longer in ring form but rather long, corrugated looking pieces. To me, this condition is an indication of things going right. I say that because when I get the MOA groups, the base shreddings are always as I described. Even when I don't get MOA they look the same. The papers I use are common, 16 and 20lb bond.

The paper ring phenomena that is being discussed here are those tightly packed and sheared little rings that often are found in the breech area or the cartridge itself. Those, I believe, are from reasons of case/chamber relationship and are indicative of problems and generally don't shoot well.


TL

[Crash Landing]

Timberlake
If you read my post, I don’t think you will find anything on which we disagree. The portion of the patch folded over the base being found in a separate piece is symptomatic of the patch being sheared off as it enters the throat and sticking there or to the case mouth. In my experience the paper ring phenomenon has nothing to do with accuracy. I wipe between shots so it really has no effect on my shooting but if you want to shoot without wiping between shots, the paper ring problem must be controlled.
The only part of your post that doesn’t jive with my experience is that while the part of the paper patch that folds over the base is found immediately in front of the shooting position, the wads carry about 30 yards down range. They are certainly not sticking together for very long after they exit the muzzle.
With thick wall brass I generally have the part of the patch folded over the base stay with the main patch remnants and with “regular” brass the patch part that was folded over the base completely separates as a distinct piece. I regularly get groups averaging 1.5 MOA (plus or minus a half MOA) with both custom made thick and regular thin case mouth walls.
So I’m a bit puzzled why you think I was talking about case length when I posted: “The only other element that needs to be considered is brass cartridge mouth wall thickness. Today’s BPCRs are mostly chambered for groove diameter, or over, bullets. Your bore diameter paper patched bullet has its base bumped up to fill the chamber as the powder ignites. As the bullet moves into the throat, it is swaged back down to groove diameter, shearing off that pesky little paper ring from the bullet base. You can clearly see this if you recover fired patches lying on the ground immediately to the front of your firing position.”