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Old August 20, 2020, 10:01 PM   #1
markr6754
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Join Date: February 19, 2018
Location: Centerville, OH
Posts: 256
135gr 40S&W Frangible Bullets - First Shots

First ladder test shots:

Okay, so I checked out all of the load data I could find for Sinterfire bullets. The two 40 S&W bullets with load data are 105gr and 125gr...nothing for 135gr. The data lists Universal w/125gr Sinterfire bullets, starting 4.7gr and up to 5.3gr. COL of 1.125”

I started my loads at 4.3gr, and 1.140” COL, loading 10 rds and moving up 0.1gr increments to finish at 4.6gr, just under the starting load for the 125gr Sinterfire. However, this is a really long bullet, and seating to 1.125” puts the ogive below the case mouth. I loaded to keep the smallest bit of bearing surface to the case mouth. Pulling these rounds apart can only be done with an impact bullet puller as there is no surface for a cam lock puller to grab. Still, I had 40 rounds loaded for this trial.

The chamber of my SA EMP lets me load these bullets out to 1.155” if needed, and still cycle flawlessly (dummy rounds), so I knew that 1.140” would be fine. But it really wasn’t, at least not at these charges.
No chrony, so I’m loading for accuracy and cycling, not velocity.

4.3gr - SA EMP doesn’t cycle, most cases fail to exit the firearm. Softer than a mouse fart. I had to manually eject the 1st round, and numerous whole, unburned kernels of Universal fell of the case.

4.4gr - Slight increase in slide action, a few cases ejected, and a few chambered the next round...still feeling mouse farts.

4.5gr - Some rounds fully cycle, some rounds fail to eject...sorta a gerbil fart, counting on 4.6gr to become actual starting load.

4.6gr - nope, this isn’t the base load either. Most rounds fully cycled, cases appear clean, most accurate load, and best cycling of the ladder, but still not a reliably functioning load. I’m thinking of starting at this charge weight, laddering up to 5.0gr and doing two ladders - one at 1.140” as shot today, and another seated to 1.135”, knowing that the bearing surface may be wholly inside the case. If this is so, I may need a bit more crimp to ensure there isn’t an edge at the case mouth.

Stay tuned.
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