Trapdoor Rifles

Why is the ‘79 carbine sight marked for 100 yards but shoots 12” high on average at that range using the standard carbine load? I’ve heard the 250 yard battle sight theory but why did the mark the sight for 100 yards then?

Think about this . . . .
If you were shooting at a man at 100 yds. distant, about all you would have for a “sight picture” is his entire body on top of your front sight.
Aiming at his lower torso, your bullet would get him somewhere between his crotch and chest . . . .equaling a dead adversary.
Likewise, if he were on horseback, you would aim at the biggest part of the mounted rider . . . . .meaning aiming at the horse, and either drop the horse or the rider.

We target shooters must remember, these weapons were meant for combat . . . .not paper-punching.

I get that, it’s just interesting that the sight is marked all the way from 100-3k yards but the 100 yard setting hits at 250 yards, this means the 200 yard setting must hit higher than that since it is higher on the ramp so in effect all the ranges are wrong. Why would you do that? I’m going to make a higher front sight and zero my favorite carbine to 100 and test as far out as I can, to see if it matches the markings on the sight. I sort of suspect that they are just numbers not really the range. I feel pretty confident that my rounds can be matched ballistically pretty perfectly to the originals since they listed the velocity of the original round and the lee hollow base 405 bullet is almost a clone of the original bullet. I will test the sight with the original blade as well. I’m lucky enough to have a 1000 yard range so the only limit will be my eyes lol. It’s just not logical to mark the sights incorrectly.

I don't shoot anymore, and never with a '79 sight, so you have me there, but I do have a fair handle on the theory. Something's missing here. Are you shooting with leaf up, or down? The battle sight (B") is not the lowest setting on the base ramp. If you have the leaf down flat, you SHOULD be better "on" at 100? Is your front sight worn down at all? Are you taking the SAME (not going to argue over CORRECT) sight picture which was envisioned by the sight's designer - not trying to be a smart-ass here, just seeking the answer. Remember, these guns were fired at the armory - the graduations are SUPPOSED to be based on those tests. Does your load REALLY match the original trajectory? Etc. Interesting topic.

What is the height of your current sight blade? There were two blades for 1873 carbines the earliest was quite short and just cleared the base. This was used on the carbines up thru the 1877 sights. When the buckhorn sight [M-79} was used the blade was made taller. If the carbine had an earlier sight and was changed to the buckhorn the blade was not changed. The early blade was .270 later .373 from barrel to top of blade. Also remember to target carbine offhand not from bench.

Interesting info! This is a star marked carbine so it is mostly early parts mixed with a new receiver and new stock ect… I will check but all my .45/70 trapdoors have shot high at the 100 yard setting. I think my 50-70 does as well. The sight does have a battle sight marking at 250 yards so these must have been originally calibrated to 100 yards right? I wish I could post pictures but I’m not a member of a photo sponsoring site.

Tom Trevor wrote: ↑Sun Jan 21, 2024 5:38 pm What is the height of your current sight blade? There were two blades for 1873 carbines the earliest was quite short and just cleared the base. This was used on the carbines up thru the 1877 sights. When the buckhorn sight [M-79} was used the blade was made taller. If the carbine had an earlier sight and was changed to the buckhorn the blade was not changed. The early blade was .270 later .373 from barrel to top of blade. Also remember to target carbine offhand not from bench.

Tom, why off hand and not off bench? Is not your aim the same either way??

Carl, Off the bench rest the recoil is more straight back. Off hand the muzzle will rise before the bullet leaves the barrel. on a target the offhand shots will print higher.

Thanks Tom, that information is really helpful.
Always learning!!

I took a look at my 1886 made carbine and compared it to the carbine with the 1879 sight an it indeed was much taller. The ‘86 carbine has a Buffington sight, did these have a taller sight than the 1879 guns? Where can I find one of these taller sight blades? Thanks for being patient with all my questions guys!