3031 in a trapdoor?

[Potsy]

We're having a shoot next Friday and a buddy of mine has a pristine late model trapdoor (Buffington rear sight). Some time ago, I loaded a Lee 405HB over 45 grn. of 3031 (the starting load in the Hogdon manual).
The manual stated 1597fps out of a 22" barrel. What we didn't think about was the 30" or so trapdoor barrel plus it was about 85 deg. that day. Velocities ran above 1700.
While I wasn't too worried about it being a gross overload, it shot WAY high (1.5'-2' @ 50 yards).
My question is, what would be a good starting load with 3031 and a Lee 405HB in a Trapdoor .45-70 that would be slow enough to regulate (minute of deer at 100 yards) to the sights.
3031 is the only powder I have on hand in that burn range. I also have Unique & 2400. I don't care a thing about loading black powder in it. Nothing against those who do, just not my bag (I do love the stuff in a muzzleloader).
All replies appreciated.

[Mark Daiute]

It's "normal" for the rifle to shoot that high at that range. The sights were not regulated for ranges that close. Hopefully someone with a better memory will chime in but I think the sights are "regulated" for a minimum of 200 yards. The answer is to substitute the original blade with a replacement blade that is taller or post a second target 12"± below the intended target.

I found 45 grains of 3031 under the .405 bullet pretty hot and hitting at least a foot high at 100 yards.

Keep us posted!

Mark

[Larry Gibson]

Some time ago, I loaded a Lee 405HB over 45 grn. of 3031 (the starting load in the Hogdon manual).
The manual stated 1597fps out of a 22" barrel. What we didn't think about was the 30" or so trapdoor barrel plus it was about 85 deg. that day. Velocities ran above 1700.


That is a little warm for a trapdoor. 39 gr of 3031 is listed as max for a 458124 at 1400 fps (24" barrel) for the trapdoor in Lyman's manual. Pretty close to what I've found also. With 35 gr of 3031 and a 3/4 gr dacron filler the velocity I measured was 1218 fps (24" barrel) with 25,500 psi(M43). 41 gr 3031 w/o the dacron filler runs right at 1410 fps and 28,900 psi(M43) which is right at max MAP for the trapdoor level 45-70 loads.

Larry Gibson

[winchester94]

Check out www.trapdoorcollector.com. It has some pretty good info. I do believe they recommend all loads should be kept under 20,000 CUP for safety sake.

[405]

Mark Daiute,
That Buffington sight is a marvel in and of itself. Way ahead of its time. Actually more sophisticated than most long range shooters can fully utilize.
Yes the lowest rear sight setting on the Buffington on the 84/88 rifle is regulated to zero at something like 200-250 yards. It also depends on whether using the U notch or the peep in the Buffington. I've found that to provide a zero beginning at 50 yards using the Buffington peep I need to use a front sight, measured from top of barrel to top of front sight, that is about .460" tall. I replaced the front blades on both my trapdoors with taller blades to provide the more practical 50 yard zero.
Easy refit. Punch out pin, fashion taller blade, drill hole in blade for pin, replace pin.


Loads, etc.
Those early recommended loads of a bunch of 3031 seem way to hot to me for the trapdoor! Probably best to keep smokeless down to BP equivalent and in the 1100-1200 fps range.

Both my trapdoor's bores have the common "generous" and well known fat groove diameters (.460-.462"). Either paper patch up to between bore and groove diameter with soft alloy flat based bullet and load over BP and use a card base wad. Or, use cast GG or GG GC bullet sized to at LEAST groove diameter to shoot over smokeless. Note most production 45 rifle molds will not come close to being fat enough for the trapdoor. My best results shooting smokeless have been with a grease groove and gas checked bullet of fairly soft alloy about 12BHN sized to .462 over a BP equivalent load of smokeless like 5744 (1100-1200 fps).

[Tom-ADC]

Check out Hodgon website they list 45 grs as okay for a trapdoor.

405 GR. CAST LFP IMR IMR 3031 .458" 2.540" 45.5 1597 17,300 CUP 48.5 1706 21,100 CUP

[Mark Daiute]

so much to learn on this website, like check primers for signs of pressure.

I had some rounds with 45 grains of 3031 and noticed (after reading about it here) that the primers had been flattened more than usual.

[NickSS]

The buffington sight on an original Trapdppr rifle will be zeroed at 265 yards laying flat with the GI service ball ammo which was a 500 gr bullet at 1230 fps. When you flip the sight to a verticle position the range graduations start at 200 yards and go up from there. The sight if set as low as it wll go will be zeroed at about 125 yards with the service ball load. I have one of these sights mounted on my Pedersoli infantry rifle and I had a front sight blade installed that I filed into zero a 405 gr lyman bullet at 1350 fps at 100 yards when the sight is laying flat. I have to raise the rear sight up to 675 yards to zero a 500 gr bullet pushed by 65 gr of FFG at 600 yards. The sight automatically corrects for rotational drift as you increase range. A marvelous sight that was way more than needed for infantry use even when it was issued. By the way I do not care when Hoddons says 45 gr of 3031 with a 4000 gr bullet is too much for routine use in a trapdoor action.

[giz189]

[QUOTE=405;1169047]Mark Daiute,
.


Loads, etc.
Those early recommended loads of a bunch of 3031 seem way to hot to me for the trapdoor! Probably best to keep smokeless down to BP equivalent and in the 1100-1200 fps range.

Words of Wisdom

[boommer]

Lyman makes a bead front sight that's a drop in and pin and works great with the buff sight.
They come in different heights. Brownells has them. .460 is what my sight height is and with 405 hb
and 1250 fps it comes in at 100 yards 2-3 low if I remember right with the sight flopped down.

Take it easy on the old girl keep the loads down to 1200-1300 fps paper and steel don't know the difference and you have plenty of sight to get you there.

[Don McDowell]

Way back in the day when trapdoors were common, blackpowder really was hard to get, and before the fake stuff came along, we shot 38 to 40 grs of 3031 with the 405 gr bullets.

[Tom-ADC]

I just picked up Lymans 49th & 4th cast bullet books both show for trapdoors starting load of 34.0 grs with 38.5 max.

[Potsy]

I was kind of surprised to see this thread come back up. I've been out of pocket for a few days.
On the second go round I loaded 39 grn. 3031. I didn't chronograph it, but it recoiled noticeably less.
It was still way high, and we wound up not tinkering with it much. It is, however, a planned project for spring.
I have done a lot of thinking, we did not need nor want above 1700fps. We really didn't need or want above 1400fps.
But I have to wonder if the Hogdon data was all that hot @ 45 grn. It said it only ran 21000 CUP. I doubt they just made it up. Look at what can be done with a .45 Colt when ran up to 21000 CUP. A .45-70 has somewhere over twice the capacity. A 405 in a .45-70 is only around 40% heavier than a 250 in a .45 Colt, and only around 30-35% longer (bearing surface). Granted, a .45-70 will only run 1300fps or so when loaded with black powder, but what is black powder pressure, is it even capable of breaking 15000CUP with a 405 and a case full of Goex FFG?
No doubt, folks here have loaded many more .45-70's than I, particularly for a Trapdoor. Hate to sound like I'm arguing with those with much more experience. 1700fps with a 405 is kinda unpleasant at the buttplate too. But I have to wonder how Hodgdon came up with 21000 CUP for that load.

[405]

No use arguing about Hodgdon data but it still seems too hot to me. To apply any data to all other guns/loads is an extrapolation of faith- that's why the disclaimer notice that accompanies all such data. So no point in second guessing that. IMO- I won't go anywhere near those loads in my TDs.

If you have a more or less regulation TD with the Buffington sight those high POIs you see at the ranges you're seeing them have little to do with the higher velocities. Those guns were regulated for zero at 200-250 yards with the lowest rear sight setting. Most straight forward way to zero at shorter ranges is to use a taller front sight blade.

[tdoor4570]

I never went above 39 gr. of 3031 in my 1884 trapdoor, with a cast bullet. It shot a little high at 100. I mostly used a case full of BP with cast and almost never used J-word bullets. Now I have an 1884 Dantish roller in 45-70 that get the same treatment, I can keep the cast in about 2 in. at 100 with the poor sights that are on it. Hope to upgrade the sight when i can get some cash and time.:-P

[DHB]

I use 38.5, 3031 in an original high wall. Its a tack driver. I had loaded up some 3031 for a Trapdoor and it was very accurate. I'm thinking (I can't find the right records) it was like 30-32 grs, It hit everything I aimed at.
Dennis