First time with trapdoor

[hiram]

I have this trapdoor. 1873. I never shot it. It's about time.

I did my usual workup of BP 2f loads.

The results are in the pic. 18 shots, one keyhole -- don't know why.

Boolit is Lee 405 HB.

Sized to 457, pan lubed, basically emmert's. No grease cookie.

The load I will use works out to 57 on my powder thrower = 63.1 grains.

I tried an unsized cartridge with an unsized bullet and it chambered. My followup will be 5 shots unsized and lubed without a g cookie and 5 with a gc. I'll try the g cookie because the barrel is long.

[waksupi]

Did you slug the bore? I'm betting on undersized boolits. Some of those Trapdoors ran pretty big in the bore.

[Skipper]

+1

The 405 HB will probably drop at .459 unsized. Try them that way. You may need to go to .460 or larger.

[TXGunNut]

Distance?

[hiram]

100 yds. the other 17 had no signs of tilting.

They bullets drop at about 460 and they chamber. I will try then unsized.

The base is hollow, but if you put a grease cookie in, the base gets filled. Is this acceptable?

[waksupi]

Yep. Just fine to get some grease in your boolit hole!
Get the right size boolit, all of those holes should be in around an inch, and all flying point on.
If the .460 doesn't shoot better, try paper patching to get up to proper size.

[Nobade]

What are those boolits cast from? Unsized and the softer the better - pure lead if you have any works great and will fill the grooves.

Droptube in more powder, that helps too. My '73 likes the full 70gr. loads under that boolit. Unsized, dip lubed.

[HangFireW8]

Which shot keyholed? First? Last?

HF

[Skipper]

You didn't load up the rifling with powder fouling, did you? Do you wipe between shots?

[Bullshop]

I would join Nobade in questioning " what alloy".
With my TD rifles both slugg about .461" and I shoot the 405 Lee HB and heavier boolits cast of very soft alloy and have come to expect about 2 moa performance or very close to it out to 500 yards.
Even with my barrel groove of .461" diameter my rifles will still shoot the same with boolits as small as .458" diameter if the alloy is soft enough and the powder charge adiquate to obturate the boolit base to make a gass seal.
When I first started with the two rifles I now have after slugging the barrels I was very close to buying a custom mold that would drop at .463" but after learning a bit about the guns I found it absolutely not neccessarry. This is even true of an old Ideal mold I have for the # 457125 that will only drop a boolit a few .0000" (ten thousandths) over .457".

[Simonpie]

While others have success with the 405 boolits, I never have. I'd try some 500+ grain like 457125. I'm shooting a fairly worn and speckled bore.

[hiram]

The alloy is 100% lead. The keyhole was the 13th shot. I used a blowtube since wiping from the breech isn't convenient.

Today I shot 5 shots unsized (.460) and lubed without a g cookie and 5 with a gc.

The results were very good IMO. I shot high, but the no grease cookie group was 4 in 3" and my fault flier. The grease cookie loads were 3 in 4" and 2 far out shots.

I'm amazed at the age / accuracy of the firearm. The sights are a little difficult to use because they are so fine. I'm shooting high but have an idea how to handle that without altering the firearm.

[Bullshop]

Shooting high at 100 yards is normal with original sights, at least so with the Buffington sight.
The nearest setting with the Buffington is 150 yards. I am not at all familiar with the 1873 sight so dont know if it allows a closer setting.
My rifles shoot the 405gn Lee HB well out to 300 or 400 yards but for the longer ranges the 500+ gn boolits do much better.

[fouronesix]

You can lower the point of impact without altering the rifle. If you have a standard TD front sight- it is simple blade held in with a small pin. Drift the pin out and simply replace the blade with a slightly taller one. Easy to fashion one out of some mild sheet steel or brass. Keep the original blade in case you want to go back to original. If it is a Buffington sight, raise the staff and at the lowest setting, use the peep. My senior eyes aren't what they used to be and the peep with the front blade is about as good a sight picture as is possible without going to glass optics.
If it has the older "sky jump" ramp rear sight then you could look around for an alternative to use in its place. Tang mounted peeps on TDs are problematic

[Larry Gibson]

+ another for not sizing the 405HB. Shoot it as cast in the TD.

Larry Gibson

[John Boy]

Hiram, use 1:20 alloy instead of pure Pb and a 6 o'clock hold ... you will like the groups

[hiram]

I'll try 1:20 -- I have it for my RB.

I checked the front sight and it is pinned --- looks like an easy fix..

[Bullshop]

But if you change the front blade your sight settings will no longer be correct.
It is very enjoyable ( for me) to go for a walk about in the hills with TD and range finder in hand. Pick out a distant rock or something you can see well in the sights. Range it with the range finder and set the sight on the rifle for that range.
If you use a load that is reasonably close to the service round hits come quite easily at long range. The service round with the 500gn boolit was between 1270 and 1330 fps.
If you dont already have Spence and Pat Wolfs book on loading for the TD do yourself a favor and contact Pat and get a copy.

[waksupi]

I bet if you tried a 500 gr. boolit, the sight would be right.

[JeffinNZ]

Keyhole? I thought he musta put his thumb through the target.

I agree on the 20-1 alloy. Maybe even 30-1 if you are light on tin/solder.

[hiram]

OK--I got ideas for shooting lower, and this is what I did -- a new, higher front sight.

Cost 1 cent and some time. It's about .420 high. I'll let you know.

I had a little laugh after the job was done. I saw a date, so I got closer-- the date was our bi-centennial, 1976.

[floodgate]

Hiram:

From the tip of the "ramrod" (really a cleaning rod) in your photo - with the multiple jags - it looks like that might be an early (1873 - 1878) .45-70 Trapdoor. Is the cut under the breechblock a straight, continuous arc, or is it flat in the center (i.e, a bit stiffer, with more "meat" in the shallowest section)? That type of ramrod is usually associated with the older '73's - though it may be a replacement - and with the "ski-jump" rear sight. (The later Buffington sight is much like the one on the 1903 Springfields - and was, in fact, their ancestor.)

The early breechblocks were said to be weaker, and were reputed to occasionally fold up in the middle with the later 500-gr. (after 1881 or so) rifle loads, though I've never actually heard of a case. I certainly would go easy on an early-type "trapdoor" - or on any of them. By all means, get the Wolf book - it's the "bible" on loading for these.

I'm old enough (early '80's) to remember going into Robert Abels' shop in New York in the 1950s, and seeing barrels (actual "hogsheads!") stuffed - muzzle-down - with .58 rifle-muskets, and .50-70 and .45-70 Trapdoors, and labeled "Your Pick - $15 each". I spotted examples of the three variant .45-70 "Short Rifles", but went home to verify them in Gluckman's book; when I got back with cash in hand, they were all gone - someone else had grabbed them. Ahhhh....them wuz the days!

Flubgate

[hiram]

Here is a pic of the breech block. Looking at it carefully, there seems to be the remnants of case hardening color.

[hiram]

I slugged the barrel. It's 3 groove as I have read.

The consistencyy of pressure pushing the slug was very even.

The slug measured .455-.456 across one land and one groove.

Has any worked up a size chart or have a similar dimension slug where they have figured out the actual groove size?

Thanks

[Skipper]

This is from an old book......I don't know if it works:

In the case of a barrel with an odd number of grooves this is measured by driving a soft lead slug into the barrel and then measuring the slug's diameter over a land-to-groove cross section and then subtracting the bore diameter. The next step is to double this figure and add it to the bore diameter to get the groove diameter.

[Larry Gibson]

Cut a strip from a beer or soda can 1/2x4". Wrap it around the slug and hold tight pinching it on one side. Snug is tight enough. Mic the diameter and subtract twice the thickness of the can strip. That will give yo a very close measurement of the groove diameter.

Larry Gibson

[Roundball]

My 1889 TD measured .462 and did well with the Lee 405HB as did a Danish RB that measured .464. It's my understanding that TD barrels tended to be .460+ and shooting a .458 bullet would be a disaster. Would suggest using the Lee bullet as cast without sizing.

[bigted]

i have the wolf book and no trapdoor but he recomends the .458/.459 boolits for all dia. barrels from .458 to .462 if memory serves...and got better then average accuracy with his loading recomendations in this exelent book.

sounds like i need a rifle and you need a book...LOL

[Larry Gibson]

Spence Wolf's loading was to replicate the original loads. The original loads were sized at .48 -.459 because they thought, back then, that the bullet needed to obturate (bump up) to fit the bore because of BP fouling. We have learned this is not the best for accuracy even with BP. The Army switched to the 500 gr bullet in 1882 because the 405 gr bullet did not have the mass to effectively obturate even with the 70 gr load. The HB is there to regualte external dimenstions not to expand ala the minie.

Wolf did replicate the service loads and if you follow his instructions the loads will give service load accuracy. However, if you size or fit the bullet to the groove diameter or larger accuracy will most often be better. I discussed this with Spence years back before he passed and he agreed. I also agreed with him though that he had achieved the goal of replicating the service loads.

Bottom line is accuracy will most often be better if the bullet fits correctly and "bumping up" is not depended on. That basic principle applies to smokeless loads as well as BP loads.

Larry Gibson

[TXGunNut]

Wow! Very informative post, Larry. Cleared up a few misconceptions I had. Thanks.

[Larry Gibson]

Much to be said for Spence's book, I have a dog eared old original copy and one of the newer ones from Wolf traders. Well worth the money even if not loading for the TD alone. Lots of good basic info on loads for the 45-70.

I only knew him for a short time and wish it had been longer, RIP Spence.

Larry Gibson

[fouronesix]

Bottom line is accuracy will most often be better if the bullet fits correctly and "bumping up" is not depended on. That basic principle applies to smokeless loads as well as BP loads.

Larry Gibson

Well said. That pretty much sums up what I have found particularly with various old, original BPCR rifles.

The only exception being paper patch-BP loading of rifles like the repro Sharps where that combination seems to favor a form of bore riding engagement of part of the nose that is patched and a shank diameter that is only a couple thous larger than bore diameter. But, I've found the same repro Sharps shoot regular grease groove best when the bullet is sized to groove diameter to about .001" larger than groove.

[hiram]

Larry, using your formula, and understanding that results are close and not totally accurate, the groove size would be .460 on my TD.

I went to the range today with 360g boolits. These were from a group buy here---flat nose, plain base. Results were not good(rifling twist?). I will retry and try the 405HB again also. I also want to try 500g.

[Larry Gibson]

hiram

A .460 is a good tight bore on a TD, my target TD is .461 so you should be able to get decent results. For BP cast the bullets of 20-1 alloy and lube with a BP lub (not sure what "emmert's" is?) I make my own with 5 parts beeswax to 4 parts virgin olive oil. Simple to do so if you don't know how ask and I'll post. The twist is fine for the 360 gr bullets if they fit the groove depth. There is not enough mass to that 360 gr bullet for it to bump up if undersized unless it is almost pure lead. Also suggest a switch to 3F BP.

Larry Gibson

[13Echo]

In my Trapdoor .45-70 and in my friends the Lee 405gr HB did best with a firm crimp over the ogive. This apparently allows enough pressure to build to "bump up" the bullet to fit the barrel. We use the bullet as cast (about 0.460") out of 30:1 alloy over 59grs of Goex ffg to approximate the carbine load. For a full bore service load I use the SAECO 181 bullet version of the 500gr govt bullet cast out of 30:1 and measuring as cast 0.460". Over 70 grs of ffg it does quite well. I do use a light crimp but it is probably not necessary with this bullet and charge. I do not use a magnum primer and I have not enlarged the flasholes like Wolfe recommends. The lube is basically Greenfrog's modified Emmert's (by volume 45% crisco, unsalted, 45% beeswax, 5% canola, and 5% lanolin). Panlubes easily.

Jerry Liles

[jed]

My original trapdoor barrel crown was oblong due to cleaning rod damage. I know if you get Pats and Spence's book alot of confusion goes away. It is mind boggling to think of how much effort they put into their book and the results you can get following their techniques.