Knurling Paper Patch Bullets to Cure Tumbling/Keyhole

[oldracer]

I posted a question and some results in the Muzzle Loading forum on the site here and it concerned my Creedmoor shaped bullets tumbling. This is with a Pedersoli Gibbs and also a copy I made with the same barrel dimensions. They were okay for several weeks and then after a month had passed they acted weird. The powder load, velocity, wad and loading methodology had not changed so finally I pulled out the calipers and found the 0.449 diameter bullets had now become 0.446! These are BACO molded grease groove 540 gain so I tried some of my paper patch smooth sided and they had also shrunk 0.003 so I figured it must be the alloy? I pulled out my Lee hardness tester and it showed a BHR of 14 so according to what I could read, they should not have shrunk as much?

I tried knurling the grease groove bullets by rolling some between two new and very course flat files from my friends at Harbor Freight and after 3 trips down the file the OD was back to 0.449. The lube grooves were not disturbed so last week I tried half a dozen and accuracy is back and the keyholes have stopped. BUT, the paper patch still tumbled so I removed the wrapping, did my manual knurl job and then new paper wrap. Yesterday I tried several with an OD of 0.448 (with paper patch in place) and no tumbling? I looked and did not find anything about knurling paper patched bullets so I thought I would speak up.

I am going to cast a bunch of new bullets of both grease groove and smooth sided with as near to pure lead as I can get as my current batch has some lino mixed in but the ingots were made several years ago and I don't remember the actual ratios? Does anyone have any thoughts on this issue or has done this? Thank you.

[longbow]

I can't say I have ever seen boolits shrink by 0.003"... but I can comment on knurling for PP boolits. In my case for smokeless loads in my Lee Enfield.

I made a mould for PP boolits for my .308 that cast at 0.301" and patched to groove they worked fine in the .308. However, when I tried them patch with thicker paper to groove diameter in my Lee Enfield accuracy was very poor.

Typically the rule of thumb is that the boolit should be at or a little over bore diameter then patch to groove for smokeless paper patching so I knurled the boolits up to 0.304" then patched to groove and they shot quite well.

I hope no-one is offended by smokeless PP comments here but the point is boolit fit has to be correct and I believe that also applies to BP paper patching.

With soft lead boolits they should be bumping up to fill the grooves but if the patched boolit is smaller than bore then possibly the un-knurled boolits are not getting started in the bore straight but the larger knurled boolits fit throat and bore better.

Just a thought.

Longbow

[451 Pete]

As the rifle oldracer is shooting is a muzzle loading Pedersoli Gibbs the bullet diameter has to be land to land measurement and not groove diameter. I also have never seen a bullet shrink by that amount and have to wonder what is in your alloy mix. In general about everyone I know that shoots one of these uses pretty much pure lead with maybe just a small amount of tin in a smooth side mold and then wraps up to the correct diameter. I have never tried knurled bullets wrapped in paper but would think it should work but with perhaps a bit more spin drift because of the additional surface area created.

just my thoughts .. Pete

[oldracer]

Thanks for the replies guys and I plan to make up some new ingots this week from pure lead to see what happens. I was surprised that they shrunk that much and I tried 3 different sets of calipers and they all read the same so that chance of error was eliminated. Probably on Friday I'll cast some bullets also to see what they do? I was not swagging the bullets so that was not the source of the shrinkage as they cast very well from both molds.

[Don McDowell]

Is it possible you were pushing the bullet thru the patch when loading?

[Lead pot]

I would suspect that that 54o gr .446 diameter bullet is close to 1.5 long. I'm not sure but I think that Gibbs rifle has a 1/22 ROT and a couple things could be going on.
Bullet is not filling the groove properly and not getting full rotation because it's stripping the lands or your getting gas cuts with that loose bullet. ???????? just a thought with out seeing a recovered bullet not to damaged..

[Chill Wills]

I would suspect that that 54o gr .446 diameter bullet is close to 1.5 long. I'm not sure but I think that Gibbs rifle has a 1/22 ROT and a couple things could be going on.
Bullet is not filling the groove properly and not getting full rotation because it's stripping the lands or your getting gas cuts with that loose bullet. ???????? just a thought with out seeing a recovered bullet not to damaged..

Kurt - The Gibbs is a 18T
Most of the people I compete with are using some form of lead-tin alloy -not pure lead. In my case 20-1 was the ticket for my bullet design.

[Lead pot]

Kurt - The Gibbs is a 18T
Most of the people I compete with are using some form of lead-tin alloy -not pure lead. In my case 20-1 was the ticket for my bullet design.

Well that is good. It should fly in a 18 ROT
I shoot with a guy that has a Pedersoli Gibbs and he said it has 22 ROT and it shoots quite well with his 1/20 alloy he said he uses.
He lets his brass rod seat his bullets under it's own weight. So they appear to be snug but not tight.

[Gunlaker]

Michael do you know off hand the length of the bullet you use in your Pedersoli Gibbs? I was talking with a fellow a while back who also said his was 1:18, but his bullets tumbled until he shortened them significantly. I think the length of the tumbling bullets was around 1.45". I've shot lots of PP Money bullets of that length in 1:18 twist out of cartridge guns with no tumbling so I found his results puzzling. His alloy wasn't anything unusual.

Chris.

[Thundermaker]

I think some of you are missing the part where the OP said that his load worked for a while, then started shooting badly. The problem is that his bullets are shrinking. I have to say, I've never even heard of such a thing. If anyone knows the cause and solution, please let me know.

[Don McDowell]

With several thousand rounds down range with patched bullets, I'm not to convinced it was simply the .003 diameter difference. Unless the bullets shrank in the patch and the patch was loose, that can cause some trouble.
Think I'ld go in that bore with a turpentine patch and see how much lead comes out.

[oldracer]

Thanks for the additional thoughts. Yes the Gibbs and my own copy both have the same 1 in 18 twist, and all other barrel measurements are the same as I had the barrel made to match the Gibbs. Both even have a "patent breach" and as I mentioned the Buffalo Arms store bought bullets than came with the Gibbs when I bought it are 0.449 diameter and 540 grain. The bullets as poured from the BACO 540 grain mold are also 0.449 so I never sized or ran them through a swaging tool.

The load is as follows after wipe and dry the barrel: Use a full length funnel, load powder charge by volume, insert 0.060 fiber wad and seat just on top of powder with very slight compression, insert bullet and the weight of the rod usually forces the bullet down the barrel to the top of the powder. If I use a paper patch bullet then I just start the wad and use a slight amount of synthetic whale sperm oil on the paper and seat both onto the powder. I noticed a few weeks ago that there was less resistance when loading the bullet and that is when the tumbling started with both types.

If I remember correctly, the outside temp was about 90 when I cast these and now air temp is 50 or so and that may have contributed to the shrinkage? I am going to try heating a couple bullets to 100 degrees or so and measure and the pop them into the freezer to see what happens?

I just saw Don's post and the patches are double wrapped and were all tight. I did look in the bore with my scope and did not see anything but will try a turpentine patch or two to see what comes out.

[longbow]

Yeah, even though I read "Gibbs" and "muzzleloading" I was thinking BP cartridge.

Nonetheless, if the alloy is soft enough it should bump up at firing. If it is too hard to bump up then that may explain it. Could it be that they not only shrunk but age hardened?

The BP PP shooters should be able to advise if BHN 14 is too hard to bump up or not.

Longbow

[Chill Wills]

Michael do you know off hand the length of the bullet you use in your Pedersoli Gibbs? I was talking with a fellow a while back who also said his was 1:18, but his bullets tumbled until he shortened them significantly. I think the length of the tumbling bullets was around 1.45". I've shot lots of PP Money bullets of that length in 1:18 twist out of cartridge guns with no tumbling so I found his results puzzling. His alloy wasn't anything unusual. Chris.

Chris - I had to go to the shop to measure them cuz it has been a while..

1.425" long
511 grains in my alloy 20-1
patched to 0.449" = snug but workable fit in the bore.

I seat the bullet while holding the rod at arms length - no bouncing! Consistent seating pressure = low ES.

1.425" going in and I assume shorter on the way out.

[Gunlaker]

Thank you Michael.It is very strange for bullets to change diameter like that. Mine don't change diameter to within my ability to measure. Chris.

[451 Pete]

oldracer ,

After giving the undersize bullets some additional thought there may be a way to salvage those and get your accuracy back. In my Whitworth I use a cylindrical paper patched bullet and had found problems from time to time. Now the Whitworth has to bump these up into a hexagonal form in order to take to the rifling. ( A significant change from the cylindrical shape. ) By using a seriously thick felt wad between the bullet base and powder charge ( about 3/8 inch thickness ) it will do this consistently so one thought of mine would be to give this a try. I am not entirely sure what happens ( internal ballistics ) but I tend to think the additional wad thickness is building just a bit more pressure to smack the base of the bullet just a tad harder before it begins its journey down the bore. I just know it works. One additional thought that has nothing to do with the bullet is I wonder if the powder has picked up some moisture from extreme temperature and humidity changes. I have seen this create issues such as a wobble or vertical stringing on long range targets at Atterbury shooting 800 yds. and further. One of the fellas was having fits trying to figure out why his load was not working and by simply opening a new can of powder the problem was cured. Well if the problem was not complicated enough already here is two more factors to add to the equation.

just my thoughts .... Pete

[longbow]

Pete:

I have no personal experience with the felt wad producing more bump up or at least more consistent bump up but have read that before. I would have figured the felt "cushion" would take away bump up but apparently it does the opposite. The felt must help seal the bore better for higher pressure or at least faster pressure rise and "thump" to the boolit.

My muzzleloading experiences are limited to patched round ball, Minies and a few Maxi's. If I get another muzzleloader with fast twist barrel I will try PP boolits. It seems like a good way to go. And I will remember the felt wad trick. Do you lube your felt wads or just show as is?

Longbow

[oldracer]

I can give the felt wads a try but the 0.060 fiber wads I am using are the same as the ones I made for my 45-70 cartridge guns so they fit tight down the bore. I tried 0.030 but they looked like shotgun blasts and went thicker. I tried several knurled paper patch loads Monday and they did not tumble but were not as accurate as the grease groove bullets. I plan to cast some pure lead rounds tomorrow after noon so we'll see how they work out.

[451 Pete]

Longbow and Oldracer ,

On lubricating the felt wads I have tried it with lube and without and other than a minor difference in change of impact at the target both ways seem to work. Keep in mind that this is shooting targets and loading off a bench and the rifle is semi cleaned between each shot with a damp patch , dry patch and cap being snapped to keep fouling consistent. The lube wad will keep that fouling a bit softer but here in Indiana we have considerable humidity ... lubing the wad may make a bigger difference without that. For a lube I use canola oil and beeswax mix and soak a pad of felt in that till the mixture cools before cutting the wads. I have to add that again this is just a suggestion as every rifle has a kind of pet load or particular combination that will work best for that rifle. I personally do not own a Gibbs ( I have four other long range muzzle loading rifles here .. a Whitworth, Volunteer ,Tryon Creedmoor and a Thomas Turner ) but I know a lot of folks that do have the Gibbs , and I can say that they all shoot paper patch in their rifles.
Oldracer just a quick question on those knurled bullets and again not knowing the distance that you are shooting these at, have you noticed any significant change in impact on the target by the addition of the knurling ? Just thinking that maybe the increase in surface area with the addition of this may impart additional spin drift ... this may not be significant until you get out there a ways.

Pete

[oldracer]

Thanks for additional ideas. I did try felt wads both lubed and non lubed a year or so ago when I first bought the Gibbs from a shooter in Texas. I also tried the Pedersoli bullet mold with pure lead and alloyed lead both with fiber wad and without a wad. The best groups came from the BACO 0.449 diameter Creedmoor nose grease groove bullets. I started working with paper patch smooth sided and had them nearly a good both double and Chase wrapped until the tumbling started a month or so ago.

To help confuse things, a couple weeks ago I had 3 bullets all touching at 100 yards BUT all 3 had tumbled! This is why I shoot these muzzle loaders and black powder as they are a really great challenge!