Trapdoor driving me nuts

[jonk]

So, I have an 1873 trapdoor. Good condition, shiny bore, mechanically sound.

I would really like to get it to shoot black powder well; I've tried 1.5FG, 2FG, light loads of 3FG with cornmeal filler, over powder wads, compression, no compression, 370, 405, and 500 gr bullets, soft lead, hard lead, rifle primers, mag primers, pistol primers (they burn through) the lot; it just doesn't shoot well. For that matter it doesn't shoot any smokeless loads well. Looking at the bore and crown it SHOULD...

Any thoughts? I know a few companies will reline a BP barrel for a fairly reasonable cost, the Freischutz Shop (Bobby Hoyt) being my first choice- but before I do that I wanted some opinions.

[nhrifle]

I would take a good, long look at the crown of that barrel as even a small nick or slightly damaged rifling there can destroy accuracy. Also, check the filing at the end of the chamber. Next step, slug the bore. Just because the bore looks good doesn't men it is of standard size. If you are shooting undersize boolits they won't slug up properly and stabilize. Might also be worthwhile to vary the seating depth.

[45 2.1]

Try the Lee 405 gr. hollow base boolit cast 50:1 lead/tin, lube it only and load in neck sized cases over 23.5 gr. of SR 4759. Crimp lightly over front boolit band, not on it.

[jonk]

Try the Lee 405 gr. hollow base boolit cast 50:1 lead/tin, lube it only and load in neck sized cases over 23.5 gr. of SR 4759. Crimp lightly over front boolit band, not on it.

I've done that very thing. Nada.

[jonk]

I would take a good, long look at the crown of that barrel as even a small nick or slightly damaged rifling there can destroy accuracy. Also, check the filing at the end of the chamber. Next step, slug the bore. Just because the bore looks good doesn't men it is of standard size. If you are shooting undersize boolits they won't slug up properly and stabilize. Might also be worthwhile to vary the seating depth.

I already load the bullets to as fat as they will easily chamber, .461". Undersized soft lead bullets with black powder isn't usually a problem, they upset nicely into the rifling. However, FWIW, the rifling on the gun measures .459".

I might do something with the crown and go from there. What do you mean "the filing at the end of the chamber?"

[Janoosh]

Apologies if I am offenslve. The Wolff book helped me greatly. Analyze the pattern of the groups. If it doesnt at least try to group, I don't believe it is the boolit. My Trapdoor wouldn't group unless I removed the ramrod. Something about barrel harmonics I couldn't grasp.

[RobsTV]

I'll second the Wolf book.

http://www.4570book.info/

Following the steps outlined finally brought accuracy to my 1886 45-70. Full case of Goex 2f, compressed with die not boolit, Hollow Base, primer pockets enlarged, etc., just as the book mentions.

EDIT: I see they now have a few books. The main book to get is "Loading Cartridges for the Original .45-70 Springfield Rifle and Carbine by J.S and Pat Wolf, 3rd edition"

They also carry the compression plug and expander, as well as #41 drill bit.

[skeettx]

Are you using a grease cookie under the bullet?
And if you have tried the hollow base bullet.

How about trying one with a gas check, 457483 perhaps, and wheel weight alloy
and SPG lube for black powder

Javaline Alox for smokeless, 12 grains of Unique
no fillers

Mike

p.s.
Interesting site here
http://www.gmdr.com/lever/lowveldata.htm

[scb]

I've tried grease cookies (and still use them), tried blow tubes, don't use them - didn't seem to help. The only thing I've been able to do in order to make mine shoot well is to run a wet patch thru the bore after every shot. It's a PIA but the rifle shoots really well doing it. I compress 60 gr of 2F underneath a "wad" cardboard disk made form the boxes cans of soda come in. Probably the same as what beer comes in. Then an .125" grease cookie made using a Montana Armory ribbon extruder. Then another cardboard disk and seat and crimp a Hoch 510 gr. boolit. Last shoot I had a 100 yd. group just a little bigger that 2". With my less than perfect eyesight over those Trapdoor sights I was satisfied.

[Janoosh]

+1 scb. I have done the same except 63 grains 2f, same wads and grease cookie, and the Lee 405 hollow base caast of soft lead. 3"-4" benched at 100 yds. I just get nervous sometimes.

[45 2.1]

Since nothing you've tried works, confirm the rifle will shoot.......... factory jacketed for group.

[paul s]

I have owned 4-5 TD's over the years and they all shot well with my black powder loads and did not seem fussy. I would be looking hard at that particular rifle?

[BCRider]

Just a thought here but while the crown may LOOK nice nothing says that it's actually square on to the bore axis.

Then there's the issue of "wandering bore drills" that produce a curved path in the barrel. If the crown was squared to the outside and the bore is actually a little non-axial then the crown won't be square on to the bore axis. And in the end THAT is the critical part as I understand this stuff.

So perhaps the key is to assume nothing and start by examining the most basic factors?

[nhrifle]

Sorry, I can't type. That should read "rifling", what some people call the leade.

[Guido4198]

You didn't provide any specific results, so I'll ask: What do you call "Shooting Well"..??? What are your expectations..?? Is it precision you're having issues with, or accuracy, or both..??
How well do you shoot another rifle with similar sights to your Trapdoor..??
Have you asked anyone else to shoot it to take "you" out of the equation..??
How are you benching it?? I've found I get better precision when my supporting sandbags are well back from the end of the barrel, with support under the butt. Barrel harmonics are a factor with that long barrel. As already pointed out, most folks find better groups with the ramrod removed.
At .461 you should be at least OK. I'm shooting a 491 gn. NEI "Badger-Browning" 30:1, pan-lubed without sizing. The other rifle I shoot black powder cartridges out of is a Browning BPCR. It has a short throat. I seat that NEI all the way down to the crimp groove using a compression die before seating the bullet. Works GREAT in the Browning, however... Trapdoors typically have a LOT of freebore. When I got my Trapdoor...also an original (1875 manufacture) my groups tightened up when I increased the C.O.L. to 2.90 in. or so.
Sorry to be getting so "wordy" here. Just trying to brainstorm what might be useful to you. I'd hate to see you have to do anything extreme to an original rifle unless there's simply no way to even get "minute-of-pig" groups out of it.

[EDG]

Have you tried pushing a round ball or soft bullet slowly all the way through the bore looking for tight and loose spots?
Another bad thing to find is a bore that is larger at the muzzle than at the breech. If you have a trumpet shaped bore it may never work well.

Tight spots can sometimes be lapped to make the bore more uniform.

['74 sharps]

What size groups are you getting and at what distance?

[jonk]

All:

I am getting about 10-12" groups at 100 yards. Similar results with both black powder and soft lead and smokeless with moderately hard lead.

I have considered enlarging the primer flash channel, but after reading about it on this very forum, decided it wasn't needed. I'm not against it, but the consensus here was it was a waste of time for black powder.

I think we're on to something with the idea of either a trumpet shaped bore or bore drilled off the center of the barrel or uneven crown; I'm going to look at those things, and try shooting with the ramrod out.

[Don McDowell]

Have you went into that barrel and done some serious lead mining? The thing could be caked up with leading from who knows how long ago, and while the bore might look shiny, part of that shiny just might be polished lead.

[mroliver77]

I vote for very careful measuring and inspection of the barrel. Find somebody with a bore scope.

Slugging a very clean barrel with a pure lead slug will tell you if there are tight or loose spots. You can really feel it!

You can sight the barrel for straightness. Research procedure on internet.