Action won't close on 45-70 re-load

[prufrock28]

I am new to reloading and can't get the action on my Winchester 1886 to close and lock on my reloads (hand feeding the cartridge). It closes fine on factory cartridges, so I measured the cases:
Factory O.L. = 2.557, Reload O.L. = 2.528
Factory width at base = .500, Reload width at base = .499
Factory case length = 2.094, Reload case length = 2.089
Factory width at neck, just below crimp = .471, Reload width at neck, just below crimp = .476
Factory bullet (300 gr) width, just above crimp = .449, Reload bullet (350 gr) width, just above crimp = .456
Factory mid-case width = 2.79, Reload mid-case width = 2.94

My first thought was that the mid-case measurement might be the issue (swelling?), but I have an inert cartridge with the same mid-case width as my reload, and it feeds fine and the action closes with no fuss. Something to do with case taper at-large?

Help!

 

[Adam in WI]

I seem to recall reading that some 1886 reproductions had very short throats. Mine didn't, and fed 500 grain bullets seated as long as the action would take. If you press a little bit on the lever and withdraw the cartridge, is there a ring or rifling marks on the bullet?

 

[OLeveraction]

Hard to tell without chamber information but more than likely it's bullet configuration.

 

[Bob3700]

Color up the cartridge with a sharpie and see where it is hitting. That should tell you where the interference is.

 

[linebaugh]

measure the bullet OD. Not knowing more I would like to know the bullet OD to see if there is something extra large there. If it is a true jacketed bullet or even most all cast bullets this is not likely the issue. Basically this would show an OD at the neck larger than the chamber allows. This is the least likely culprit.
Considering the bullet OD is not the issue you may be crimping too much and seating in one step causing a bulge right below the crimp. To fix this either reduce the crimp and/or seat in one step then come back and crimp in the next step.
Last thing that may be causing this is the bullet is engaging the rifling before the bolt closes. This would require deeper seating to get the ogive set back enough to allow chambering without seating into the lands prior to full close on bolt.

 

[Coyotefurharvester]

Lyman 45/70 ammo checker is 25-26$ on flea bay. Makes die adjustment, ammo fitment easy. I also believe over crimping (bulges brass) is an issue for new reloaders as the case length must be very consistent, plus crimping isn't a feel operation. Always check brass for fit prior to loading, makes diagnosing problems easier as you know what part of the operation is causing problems. Flaring case mouths also is/can be a fitment issue.

 

[dellet]

From your numbers, unless it’s a custom chamber, the cartridge is probably loaded too long.

What was the recommended length from the bullet manufacturer?

If you look at the chamber drawing below. The .450” portion of the bullet will hit the lands of the barrel at 2.179”. It will depend on the shape of the bullet nose. But your lodes quite a bit longer than the factory round and the diameter of the new bullet in front of the case neck is larger than bore diameter. The factory load bullet was positioned so the lesser than bore diameter portion of the bullet was all that was outside the case.

If you can mark a bullet at the .450” diameter of the nose, and seat the bullet deep enough where that portion is shorter than 2.170” you should be fine. It using manufacturers length would be best.

If you are using manufacturer length, then make sure the data is for a lever rifle, not a Ruger.

 

[OLeveraction]

Get a Hornady, OAL Gauge, and a Lock-n-Load Modified case.

 

[prufrock28]

From your numbers, unless it’s a custom chamber, the cartridge is probably loaded too long.

What was the recommended length from the bullet manufacturer?

If you look at the chamber drawing below. The .450” portion of the bullet will hit the lands of the barrel at 2.179”. It will depend on the shape of the bullet nose. But your lodes quite a bit longer than the factory round and the diameter of the new bullet in front of the case neck is larger than bore diameter. The factory load bullet was positioned so the lesser than bore diameter portion of the bullet was all that was outside the case.

If you can mark a bullet at the .450” diameter of the nose, and seat the bullet deep enough where that portion is shorter than 2.170” you should be fine. It using manufacturers length would be best.

If you are using manufacturer length, then make sure the data is for a lever rifle, not a Ruger.

View attachment 1527104

Thanks! Great info. Had no idea SAAMI drawings were available online. Doing a sharpie test, it's clear that the bullet is rubbing enough that the action won't close completely, although very close, close enough that if I rotate the cartridge in a particular war, I can get it to close. Here's a really naive question, Why is the bullet diameter slightly larger than the bore diameter? Is that minor difference approximately the same across all cartridges?

 

[prufrock28]

I seem to recall reading that some 1886 reproductions had very short throats. Mine didn't, and fed 500 grain bullets seated as long as the action would take. If you press a little bit on the lever and withdraw the cartridge, is there a ring or rifling marks on the bullet?

Thanks, there are marks on the bullet.

 

[prufrock28]

Color up the cartridge with a sharpie and see where it is hitting. That should tell you where the interference is.

Great idea. The marks are visible in this pic. This batch of reloads fit until I applied crimping using a Lee Factory Crimp die. Perhaps the crimping was too aggressive and disturbed the bullet?

 

[divingin]

Here's a really naive question, Why is the bullet diameter slightly larger than the bore diameter? Is that minor difference approximately the same across all cartridges?

Generally always are, to ensure gas seal as the bullet engages the rifling. Usually figure a thousandth over bore diameter; lead bullets can be 2-3 thou over (they swage down on firing easier than jacketed.)

 

[prufrock28]

measure the bullet OD. Not knowing more I would like to know the bullet OD to see if there is something extra large there. If it is a true jacketed bullet or even most all cast bullets this is not likely the issue. Basically this would show an OD at the neck larger than the chamber allows. This is the least likely culprit.
Considering the bullet OD is not the issue you may be crimping too much and seating in one step causing a bulge right below the crimp. To fix this either reduce the crimp and/or seat in one step then come back and crimp in the next step.
Last thing that may be causing this is the bullet is engaging the rifling before the bolt closes. This would require deeper seating to get the ogive set back enough to allow chambering without seating into the lands prior to full close on bolt.

The bullet OD is .457, so not too big, but sharpie test shows a rub on the bullet, so probably too far out. Reapplying the seating die and pushing the bullet down a bit, changes OL to 2.530", and the problem is solved. Thanks!

 

[dellet]

Thanks! Great info. Had no idea SAAMI drawings were available online. Doing a sharpie test, it's clear that the bullet is rubbing enough that the action won't close completely, although very close, close enough that if I rotate the cartridge in a particular war, I can get it to close. Here's a really naive question, Why is the bullet diameter slightly larger than the bore diameter? Is that minor difference approximately the same across all cartridges?

Bore diameter, groove depth, and caliber can get confusing at first.

Using a 30 caliber, .308 bullet makes it easier to explain.
The hole is bored to .300, the grooves are then cut .004” deep. So the bore is .300”, groove .308”. Bullet is .308” if jacketed, but slightly larger if cast or plated. Gotta fill the gap between the bore and the groove depth. The bullet will first cantacf the smaller diameter of the bore, the lands left behind after cutting the grooves.

Bullets expand to fit the grooves, obturate, different materials do that differently under pressure, it’s to keep the gasses behind the bullet. Gas cutting a bullet due to a bad seal plays with accuracy and velocity.

If you can rotate the cartridge and the chamber closes. The bullet may not be seated straight. Or something might have got out of alignment when seating. You might be able to roll the cartridge on the table and see a wobble.

Another cheat to check loaded length. A 45 acp case will have very close to a .450 diameter inside neck. Use that as a comparator insert if you have one. A sized 45-70 could work, it just gets awkward. Run it through the sizing die and check inside diameter without expanding.

Knowing the exact bullet and what you’re shooting like be helpful. Some one else may be shooting that exact combination.

 

[prufrock28]

Lots to learn. This site has been fantastic! Thanks to all for the great advice.

 

[Coyotefurharvester]

Problem is you stated 2.528 as the overall length of your reload? Now 2.530 fits?

 

[prufrock28]

Problem is you stated 2.528 as the overall length of your reload? Now 2.530 fits?

You're right. I thought maybe I made a typo, but I re-measured the batch and the OL really didn't change. I guess I've got to conclude that the Lee Factory Crimping die pushed the bullet off center and running them back through the bullet seating die trued it up again. I'm not blaming the crimping die (yet) because I probably don't have it adjusted properly or am being too heavy handed with it.

 

[Kalitrazescapee]

I have a no1? Roller that was built by Bill Morrison when was in Bangor Maine,and I cannot compress a load or load a cast bullet as cast because Bill chambered this rifle with a min or match dimensions.
I hav'nt found out how it got to west coast,and from stamping on receiver,he may have built this in 1977.