24. September 2021 kl. 10:17:23
forum.svartkrutt.net

Author Topic: Kammerlader bullet and ball sizing thread.  (Read 479 times)

18. August 2021 kl. 11:10:45
Read 479 times

ironoxide


I'm starting this thread in hope of getting more information about exact diameter of conical bullets and balls that work well for people with Kammerladers. There is information like this in various places online, but I think it would be very useful if in addition to bullet diameter the barrel bore and groove diameter was known in each instance (and perhaps chamber diameter and a picture of a forcing cone).

We all know what the official dimensions are supposed to be, but there is variation in manufacturing even today so I suspect back then there was even more variation.

This is the reason for this thread, to see if there is some rule regarding bullet and ball sizing with regards to the rifling.

The bore diameter is the smaller of the two dimensions. The groove dimension is the larger.

I have a Liege made M1851 Swedish navy model with rifling that has hexagonal lands and rounded grooves of 14.8/15.4 mm dimensions (0.5826/0.6062 in).

I received information of slightly undersize bullets working well for Torgeir
- his bullet is 0.587,
- I believe his groove diameter is between 0.600~0.610
- accuracy he mentioned was 10cm (4in) at 100m. Very good IMO
I have some of his bullets on the way, but I wanted to do some experimentation in the meantime.

So far I've tested an oversized conical bullet. The shape is very similar to 18-bore kammerlader bullet, but it has been scaled down to 15.63mm(0.615) diameter. I made the mold myself. The accuracy (as should be expected somewhat) was abysmal. I was frequently off paper at 40m. I tried 2f and 3f powders, but I limited the loads to 70gr of 2f and 60gr of 3f due to overpressure risk of an oversized bullet. If I cleaned the bore and I put enough 16ga shotgun cork wads over the powder so the bullet was as much forward as possible (almost rubbing it's nose during breech closing). I did manage to get 4 shots in an about 3in horizontal group (vertically on the same level) at 40m, but then I couldn't replicate the result. Perhaps because I run out of cork wads which I attempted to reuse :-) Next time I'll take polenta with me to the range.

Next I'll be trying the same bullet in smaller diameter. I haven't tried casting with a new mold, but I expect it to cast 15.13mm(0.595) bullet.

For the sake of completeness here are details of one 18-bore Norwegian Kammerlader I found online.
Bore 16.78 (0.660 in)
Groove 17.84 (0.702in)
(This is very close to spec).
An article on svartkrutt.net says original conical bullets were likely between 17.25 to 17.5 (0.679 to 0.689 in).

For those that haven't slugged the bore of their Kammerlader I provide a short instruction how to do it here.
Make sure your bore is clean, best to do this after cleaning and oiling the gun. Measure the groove diameter with calipers roughly. This is the maximum diameter bullet that should be used for this task. It is critical you only use a pure lead projectile to avoid getting it stuck in the bore. If you have a round ball or conical bullet that matches this diameter or is slightly smaller that's great. If you don't, take a smaller bullet, put it on an anvil or vice and give it a gentle tap with a heavy hammer. Measure again, and repeat until desired diameter has been reached. Grease the slug with the usual grease you use. If it has grease grooves make sure they are filled.

Open the breech of the gun, make sure it is unloaded and with breech open arrange it vertically muzzle up. Put the bullet or ball in the muzzle and tap it gently with a wooden or brass mallet until it is almost level with the muzzle. Then take a short metal rod set it against the bullet and continue. I use a nipple wrench for this. I then switch to a long screwdriver. Once the bullet is a good way in take your ramrod with a matching jag and tap it by hand the rest of the way so it falls out through the open breech. First 2-3 inches are the hardest, the rest of the way is fairly easy with proper lubrication.

18. August 2021 kl. 18:51:38
Reply #1

ironoxide


This is the bullet design I'm testing currently.



One of reasons for starting this thread is to find out what round ball sizes work for people with kammerladers(preferably Swedish ones, but even results from Norwegian ones can be useful).


19. August 2021 kl. 14:56:59
Reply #2

Torgeir


Your bullet design looks quite a bit like the ones I just sent you, and I am not surprised that accuracy was poor. It corresponds with my own experience with bullets at .60 caliber or larger. I should think you will have better results with the .595-bullets you mention are next up.
At first I was using a carton "cup" for my bullets, to get them centered on their way out of the breech so they don't "stumble" entering the bore. This is the same trick we use in Norwegian kammerladers, but it turned out my Swede didnt' need this to shoot just as well without carton. I suppose the first bullets you tried filled the breech with not much leeway left?
As for round balls, I have only tried this in the Norwegian kammerlader. They were of .69 caliber, and didn't group that well. The point of impact at 50 meters is higher with a round ball, as I'm sure you're aware of.
Torgeir

19. August 2021 kl. 16:16:24
Reply #3

ironoxide


Thank you for the reply and your previous posts in another thread which helped me a lot :-)

I only tested those oversized bullets because I was curious.

I'm interested in comparing them all :-)

You are correct in thinking those 15.63 bullets were a sliding fit in the chamber. I believe the chamber is slightly conical shaped as they went in easily, but from 2cm in they got tighter and tighter.

The design looks similar to bullets you've sent me, because I used the link to accurate molds page you sent as "inspiration" together with the Norwegian kammerlader pointed bullet described in the book. The length of the bullet, depth of grooves are all scaled down dimensions from the book.

Since I wrote the previous post I cast more bullets from the smaller mold. They are 15.03~15.05mm. I tested them at the range today and I had acceptable results with a load very similar to yours.

I used 70gr of 2f (Polish "Złoty Stok" powder), 55 grains by volume of semolina, then the bullet(no cup, no wad) and grease on top. This load shot quite well, but I had very little of my 2f powder with me so I tested 3f(Czech Vesuvit LC) in a modified load as well.
62.5gr of 3f, same amount by volume of semolina, then the bullet (grease grooves empty) and again grease on top.

With both of above loads I had acceptable accuracy. I was shooting at only 25m (after the abysmal accuracy of previous oversize bullets, and due to the sights being set low and to the left). That acceptable accuracy was bullet holes touching and overlapping slightly.

I tested many different ways to load, except the cup merhod. I intend to test paper patrons as shown in Øyvind's youtube video in future too.

I noticed significantly worse accuracy when the bullet was deep in the chamber. The best accuracy was found by using a filler so the total load volume under the bullet was 125 grains(by volume).

Another interesting observation is that when I was putting the grease in bullet grease grooves instead of on the top I had worse accuracy. I also had my filler (semolina) collect in the chamber sealing ring. It was quite an inconvenience having to clean up semolina crud between shots.

When grease was placed on top of the bullet there was no semolina crud anywhere. It seems grease has sealed the ring so no semolina could get there.

Grease that I used is so called "Matthews grease". It contains 50% beeswax, 38% neatsfoot oil, 12% liquid garden soap. It is pretty hard in room temperature. I have to try a softer grease in future.

I hope to be able to test bullets sized 15.45(one thou over rifling depth), 15.2(same area as the rifling) in future and of course ones you've sent me.


19. August 2021 kl. 17:31:19
Reply #4

Torgeir


This is interesting and promising results. A rather soft grease on top is the normal procedure shooting kammerladers here in Norway. Maybe polenta instead of semolina would reduce the clogging, as it is normally coarser. Coffee is also sometimes used as a buffer.
Torgeir