Sensitive to COAL

[lklawson]

Well, not that it's any surprise, but my R51 is sensitive to Cartridge Over All Length (COAL).

In order to make my barrels short leade/throat safe with the lead cone nose bullets, I had to seat the bullets deeper and reduce powder charge to prevent over-pressure.  Well, it looks like the load is safe and not over-pressuring but the shorter COAL is causing feed problems.  The COAL is 1.08".   The feed failures is a live cartridge stove-pipe.  Basically, as the cartridge is stripped and feeds up the ramp toward the chamber mouth, the nose goes up too high and misses, popping out of the mag, point up, with the slide closing on it.

My R51 really prefers an COAL of about 1.10" to 1.125" (standard for jacketed bullets).

So if I want to use Hard Cast bullets, I need to find one with an appropriate ogive and length (which also means weight).  As I wrote before, I may just end up giving up and sticking with 115gr FMJ.

Peace favor your sword,
Kirk

[Zenshot]

Are the cast bullets that you're using too short to seat at a longer OAL ?

[lklawson]

Are the cast bullets that you're using too short to seat at a longer OAL ?

No.  They can seat longer.  But that won't solve my particular issue.

Seating at standard, recommended, COAL for these bullets causes the bullet to engage the rifling when the cartridge is loaded.  Seating it to longer COAL would be just as bad or worse.  In order to make these bullets, once loaded in a cartridge, NOT engage the rifling they need to be seated deeper than standard/recommended COAL.

But once I get them seated deep enough that the cartridge is safe in the chamber, the loaded cartridge is too short or reliably feed.  Mostly a live cartridge "stove pipe" which is indicative of the OAL being so short that it "misses" the top hood of the chamber or it "pops up" too fast out of magazine during feed.

The problem is with the ogive of the bullet.  This happened with 3 different HC bullet shapes.  I had hoped that the Cone Nose shape would be OK, but I guess that the cone shaped ogive doesn't flow down far enough.

The OAL and ogive of standard 115gr FMJ and 135gr Critical Duty both work just fine.  Neither engaged the rifling during plunk and both feed reliably.

The bullet shape/ogive of the 115gr. HC from SNS Casting is much closer to that of the standard 115gr FMJ and it does not engage the rifling (plunks fine) but the OAL is just a tad too short and it had feed problems (as above). 

I still have about 700-800 bullets from MBC in 115gr HC and 124gr HC CN that I will just load up for my other 9mm guns.

I might try SNS Casting 115gr. again and seat to a longer COAL to try to fix the feed problems, but I'll have to be paranoid about plunk testing.

I should probably just switch to FMJ but they're more expensive than HC (even coated) so I don't really want to.

Peace favor your sword,
Kirk