What happened with my loads?

[hightime]

As many know I've been searching for a 45 Colt load for my 1873 Uberti. I have heard several times that the chamber sizes are rather large and blow by and soot on the cartridge sides are common. I thought I'd try a few without a total resize. I sized them some just to get some bullet tension. I'm very picky about the charge wieght. I weighed each one. Pretty stout load, 9 gr. Unique. 250 RN Rem Swaged .455 dia. ....The first one shot as it should but, then second a weak pop. Same with the third. I only had those three in the gun. I guess what happened was the lead moved, but if pulled out, wouldn't it not load? If the spring pressure pushed the bullet in wouldn't it increase pressure?

I never had this happen before. The can of Unique is good I know that. I'm sure the powder load was good. The primers may have been a few months old, but they havn't been outside the box. Any ideas?

Owen

[Terry Murbach]

YOUR ANSWER IS SPECIFICALLY NOTED IN YOUR POST !!

NOW THINK.......

YOU " SIZED 'EM.... SOME..."

YOU USED A BULLET WITHOUT A PROPER CANNALURE TO POSITIVELY STOP A BULLET GOING INTO FURTHER INTO THE CASE FROM FOLLOWER TENSION.

AND FURTHERMORE.....YOU " SIZED 'EM ....SOME ".... SO THE BRASS DOES NOT FIT THE CHAMBER PROPERLY[PERHAPS..] AND THE FIRING PIN BLOW IS CUSHIONED[PERHAPS?]

DID ALL THREE PROJECTILES CLEAR THE BARREL ??

THERE ARE SEVERAL OTHER ERRORS IN YOUR LOAD FOR THAT GUN BUT THAT IS ENOUGH TO THINK ABOUT FOR NOW.

[J Miller]

Owen,

There is the biggest reason I full length size ALL my .45 Colt ammo. I've used a bunch of that bullet. When full sized, weather by carbide or standard sizing die, expanded and properly crimped after seating the bullet will not push back in and it will fire properly.

Here is one thing about Unique. It doesn't burn good if there is insufficient neck tension. There needs to be resistance to delay the bullet so the powder can properly ignite. Without it you get inconsistent ignition and gross variations in velocity.
If you have proper neck tension you can almost do without the crimp ... almost.
But without neck tension a heavy crimp is all but useless. It really takes both.

When you said: "I sized them some just to get some bullet tension. " , that told the story. Your sized some was not enough.

Those who neck size their revolver cartridge ammo (a practice I do not agree with) usually use a carbide die which will over size the cases when they are full sized. They size down to where the bottom of the bullet would be and usually achieve good neck tension. I think I remember you saying you used a standard steel die, if so you didn't have any neck tension to speak off and when you fired the round that had the week pop the bullet simply moved forward when the primer fired and the powder did not get a good burn. It was a squib load.

If you are using a standard die, full size those cases all the way and you will get better results.

Been there, done that.

Joe

[Nath]

I have no idea about 45LC however Unique in some shot shell loads needs a mag primer!

May be worth considering!?

Critics correct me if needed!

N.

[J Miller]

Nath,

I don't know anything about shot gun shells, but I have used Unique for nearly 40 years. There is no handgun load with Unique I can think of where a mag primer is required.

Joe

[AJMD429]

I know some powders need proper pressure build up to burn right - 2400 comes to mind.

Dumb question - doesn't proper pressure come more from crimping, than from sizing...?

If that's the case, couldn't a person "size them just a little bit", but still get a proper pressure from crimping firmly...?

The minimal sizing may or not stop the blowback/soot issue, but it seems like it wasn't the problem - the lack of firm crimp was.

[hightime]

I think the answer is yes. I just got in from a new batch. I sized them halfway down and they shot great. Now I know how important bullet tension is.

Owen

[Terry Murbach]

I know some powders need proper pressure build up to burn right - 2400 comes to mind.

Dumb question - doesn't proper pressure come more from crimping, than from sizing...?

If that's the case, couldn't a person "size them just a little bit", but still get a proper pressure from crimping firmly...?

The minimal sizing may or not stop the blowback/soot issue, but it seems like it wasn't the problem - the lack of firm crimp was.

NO CRIMP OF ANY TYPE CAN REPLACE TIGHT---TIGHT !!!---BULLET SEAT IN A CARTRIDGE CASE. IF THE BULLET IS NOT TIGHT ALREADY THE CRIMP HARDLY DOES A DARN THING OTHER THAN GETTING THE CASE EDGE OUT OF THE WAY.
IN PISTOL CARTRIDGES I LIKE TO SEE THE BOTTOM EDGE OF THE BULLET SHOW ON THE OUTSIDE OF THE FL SIZED CASE AS THAT IS PROPER AND TIGHT BULLET SEAT WHEN THAT BULLET IS PROPERLY SEATED. THEN AND ONLY THEN WILL A PROPER CRIMP FINISH THINGS OFF IN FINE STYLE.

NATH, UNIQUE NEEDS MAG SHOTSHELL PRIMERS BECAUSE OF THE VERY LOW PRESSURES IN SHOTSHELL CARTRIDGES. OTHERWISE UNIQUE WILL BURN LIKE CORDWOOD .

[stretch]

As usual, Terry hits the nail on the head.

Sizing the case should ideally make the case interior
diameter a thousandth or so smaller than the bullet.
This forms a gas seal, and also holds the bullet for just
a fraction of a second, which allows the powder to burn
in a manner that lets pressure build enough to give
expected performance.

I've always considered crimps to be mainly for preventing
the bullets from moving in the case in the event of heavy
recoil or rough handling.

I've read that a heavy crimp can allow some powders like H110
to fully ignite and provide more consistent performance. One of these
days I'll have to try some heavy magnum revolver loads loaded singly,
both with and without crimp, to see if there's any truth to that.

-Stretch

[1894c]

thank you...great info on this post... :)

[Nate Kiowa Jones]

I think the answer is yes. I just got in from a new batch. I sized them halfway down and they shot great. Now I know how important bullet tension is.

Owen

As you have found neck sizing enough to get good tension will work and you don't have to full length size either.
I bet you will get even better results using the TrailBoss powder.

[Nath]

Thanks Joe and Terry

N.

[JRD]

Good information on neck tension. It's important across all reloading, but especially so with cast bullets and tubular magazines. I learned about neck sizing the hard way when I first started reloading for an 1873 in 44-40. I had to pull the mag tube cap on my 1873 a couple times to free up the action when a bullet completely telescoped inside the case and jammed the carrier. No amount of crimp will make up for a loose fit of the bullet in the case neck.

If you have any of your first loads left you could try an experiment. Load them singly so you are certain the bullets are not being pushed inside the case, and see if they shoot more consistantly. You need to fix the neck tension either way, but this would tell us for curiosity sake if its bullet push in or inadequate neck tension that's the root cause of your problem.

Jason

[earlmck]

this would tell us for curiosity sake if its bullet push in or inadequate neck tension that's the root cause of your problem.

It was all in the lack of neck tension with Unique powder, Jason. If the bullets were getting pushed in he'd have ended up with high pressure problems from the reduced case capacity; not the low-pressure blooper problems he had.

A normal load can turn into a real bomb if the bullet gets pushed back down into the case. Just out of curiosity I took hightime's load (9 grains Unique, 250 grain bullet) and plugged it into the QuickLoad ballistic program. Program said this should be about 16,000 psi, or a normal 45 Colt load. Then I just changed the C.O.A.L figure to equal the case length (as though the bullet got pushed down flush). Right at 35,000 psi! (but another 100 fps velocity ) So if the bullet gets shoved back in the case, you really don't want to touch it off in your 1873.

I might admit here that although I've known for years that bullets shoved in too deep raised pressures considerably, I didn't realize it might be this dramatic. And QuickLoad may not be exactly right here, but I'll bet it isn't far wrong either.