Trapdoor bullet diameters

[Etienne Brule]

Hi

Last year, I got a Springfield Trapdoor 1884.

I spent "some time" to clean it.


So here I am with that gun after cleaning...

I shooted with some .459 405 grains bullets...

WOW only KEYHOLES . . . . . . . . .

I slug the gun: WOW !!

- groove diameter: 0.467
- bore diameter: 0.461

What would you suggest as mould diameters ?? I was thinking a a custom mould with some .468 diameter....


Gerald

[herbert buckland]

RCBS have a couple of 468-480 gr moulds that would work

[Nobade]

You are sure of those numbers? measuring a 3 groove slug isn't easy unless you have the correct V-anvil mic. You really can drop a .461 (or .4605) pin through the barrel?

The reason I ask is Trapdoors are usually quite consistent at .450 bore and .462 groove. If yours is that big you'll likely have to breech seat or muzzle load bullets to get it to work since you're not going to be able to chamber a cartridge with a bullet that big in it.

[Ragnarok]

That's Martini Henry size!!

Mine works well with my Lee mold 405gr or 500gr cast bullets...both molds make bullets at plus or minus .459(I don't resize 'em)

[Hardcast416taylor]

My 1884 TD shoots .462" as cast slugs quit nicely. I got the mold from a maker on this site, Richard Doughty.Robert

[45 2.1]

Trapdoors will normally accept 0.462" diameter boolits. The real trick is to not use a harder alloy. Stick with a lead/tin alloy of about 25:1 and you won't have trouble with accuracy.

[Simonpie]

In mine, I find bullet diameter makes modest differences in accuracy. Mine likes .459 best. However, it will keyhole all over the place with a 405 grain bullet of any sort. 500 to 530 grain straightens them right out.

[bigted]

should find out the twist rate of your barrel also as this will/should dictate what boolits it will most likely want. might also ensure that it has the origanal barrel on it./// sleeved??

the wolf book is a valuable read for the springfields also. mine is getting dogeared with searching for certain writings/thoughts of the writer.

[Grapeshot]

If you use bullets cast of 30:1, lead:tin, or softer, and are 500 grains or heavier you will see a big difference in accuracy. The softer lead will bump up and obturate when kicked in the butt with a 70 grain charge of 2Fg.

405 grain boolits need to be hollow based to obturate to get any accuracy, especially when using the carbine load of 55 grains of 2Fg.

[John Boy]

The groove on my 1872 is 0.454 and I usually shoot 405HB bullets cast at 1:30 shooting black powder. It's common for the Trapdoor groove diameters vary all over the place - reason the hollow base bullets shoot more accurately

Two weeks ago, after fiddling with the ladder sight for sighters, manged to knock down Rams at 500meters and one on a 1000yd target. Was using the 457124, 385gr bullet with 70grs of FFg cast at 1:30

[chuebner]

The M1888 Springfield I have slugs at .450X.460. The Rapine 460-500 boolit, the Lyman 457125 or 457132 beagled to .461 with 30:1 lead, 65gr Schuetzen 2F and Bullshops NASA lube will shoot honest 2.5" groups all day if I lay off the coffee at the range. Get the Wolf book and follow the recipes.

Good luck with your new toy.

Charlie

[bob208]

speaking from esperince i have found the 84 trapdoors with the rod bayonet to have large bores i have had three of them over the years. the first one needed a .465 bullet cast soft and 500 gr weight. the second went to .467. the thrid come out to .461.

[bc1]

Hi guys. I ran across this thread and have a question since I've been looking for a 73 springfield .45-70 carbine and have a 73 model uberti .45 revolver. I think the original long colt boolits had a recessed center like the rifle. Does anyone make a mold that will leave the hollow recess in it? There was a reason the gov put that in the boolit but it slips my mind right now as too why? Thanks.

[Larry Gibson]

This might help........I don't know how to make it larger here. If someone does PM me your email and I'll email it so you can post larger?

Larry Gibson

[Etienne Brule]

Hi

I thank you all for those answers.

So I made some measurements:

twits: 1 /22

bore diam: 0.461

groove diameter: 0.465

I will look to get a custom mould.

thank you

[Nobade]

That still sounds like a mighty big bore diameter for a trapdoor...

Do you do any paper patching? Sounds like you could patch up normal 45-70 boolits and see how it does before investing in a custom mould.

[HARRYMPOPE]

my ratty bore trapdoor took a .465 GC bullet and linotype alloy to get it shooting.

George

[Nobade]

It's not the groove diameter I question. It is the bore. Rifling only .002" deep? I don't think so. Either way it's easy to make .459" boolits be .465" with onionskin paper. Then it will likely shoot well.

[twildman]

You can get the Lee hollowbase mould for not much dough and never look back, as I have....

[nicholst55]

This might help........I don't know how to make it larger here. If someone does PM me your email and I'll email it so you can post larger?

Larry Gibson

Right click on the image, open in new tab, then hold down the control key and hit the '+' key until its big enough to read.

[Boz330]

Right click on the image, open in new tab, then hold down the control key and hit the '+' key until its big enough to read.

Thanks Nicholst55 you learn something new every day. I just picked up a 75 made 3 groove. Need to get out and shoot it.

Bob

[curator]

Don't look to the hollow base on the Lee .459/405 boolit to provide bore sealing expansion. It is too small and only there to provide the correct weight and length. When using real black powder and boolit hardness of BHN 10 or under, diameters as small as .459 will usually shoot fine. Harder bollits may need to be larger. Smokeless powder loads should be at least groove diameter or be loaded with a granular filler like Cream of Wheat or Plastic Shot buffer. Original 55 grain carbine loads had paste-board wads under the bullet to seal the bore and create higher pressure. Believe O. Mac Kagen's trapdoor measurements. He was a treasure to cast boolit shooters, using his 3, 5, 7, and 9-sided V-micrometers to get us accurate measurements of bore slugs for free for decades.

[StrawHat]

... Original 55 grain carbine loads had paste-board wads under the bullet to seal the bore and create higher pressure...

The first carbine loads used a cardboard tube to take up space in the cartridge. Then came the wads and the final iteration of the load had the bullet pressed down to meet the powder, no wads. All worked, not sure which is the better solution.

[13Echo]

In my 1884 I find a firm crimp over the ogive of the Lee 405 makes a significant difference in accuracy. I think it allows the pressure to rise enough to cause obturation before the bullet moves. I use 59grs FFG and no wads with the bullet seated to allow the crimp. Very pleasant load. The 500 gr 1881 bullet seems to have enough inertia to not need the crimp with a full house 70gr load. All bullets are cast from 30:1 alloy and both cast at 0.460" (1881 SAECO) to 0.462 (Lee 405HB).

Jerry Liles

[RobsTV]

.......When using real black powder and boolit hardness of BHN 10 or under, diameters as small as .459 will usually shoot fine......

That there is the key with an original trapdoor.
With my 1884, dozens of rounds shot horribly inaccurate using a half dozen different powders until I switched to Goex FFG (full case slightly compressed) and soft lead. Instantly fixed and is now a blast to shoot.

[Larry Gibson]

Even soft cast bullets of groove or larger diameter will shoot more accurately than any bullet swaged down only to be "bumped", obturated, etc. back up again to fill the groove depth on firing. I shoot bullets of 210 - 500 gr in my M1884 target rifle and bullets of .4615 - .465 will always shoot more accurately than any bullet sized down to .459. That is with smokeless and BP loads.

If a larger diameter bullet will chamber then there is no sense and usually less accuracy by swaging/sizing it down to .459 just because........

Larry Gibson

[218bee]

Try a LEE 405 hollow base and cast them soft. I personally have had good luck with that mold in Trapdoors. And its a cheap start

[Abert Rim]

Hmmm. Things to ponder. I just bought an 1884 ramrod-bayonet rifle from Al Frasca. Wonder if it will have the larger groove diameter. I have the Lee 405 HB and the old Lyman 457125.