24 October 2022
I had a puzzling experience with my .45-70 reduced loads today and would appreciate any analysis of the situation that you may be able to offer.
The bullet vendor offered a table of loads supposedly supplied by Lyman. The bullet is said to be Lyman #457130 (150 gr.). I selected one of the milder loads, with the slowest burning powder in my possession, one with a bulkier powder charge (21 gr of IMR 4227). I seated the rather short bullet just so the lube groove was covered and gave it a light crimp with a Lee Factory crimp die.
This load has a volume of about 1.6 cc, and the case has a published useful volume of 4.06cc.
I used a Ginex Large Rifle primer. The bottle of powder was new, was not previously opened and was ordered this month.
I shot about 100 other loads today that used primers from that same tray and lot with no problems.
The first round fired with a report similar to that of a .22 LR, including the sonic crack. The bullet hit the target at the point of aim.
The second did the same. On a whim, I took a look inside the barrel, from the breech to see if there was any unburned powder. There appeared to be powder on the barrel surface from the chamber forward for about ¾ of the barrel length but all in the 3:00 to 6:00 quadrant.
The third round appeared to be a dud from the sound (only heard the hammer fall), but case ejected without the bullet or powder. The bullet did not impact the target. The barrel was inspected and was clear.
Round No. 4 appeared to be a dud from the sound (only heard the hammer fall), but case ejected without the bullet or powder. This time the barrel was blocked. Using the cleaning rod, the bullet was found to be 6” from the muzzle. The bullet was driven out with a single palm strike on the SS cleaning rod
I stopped shooting this load at this point.
I fired about 30 other .45-70 loads without incident. They were standard power loads.
It appears that either IMR 4227 is a bad powder for .45-70 reduced loads, or I got a bad bottle of powder.