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Type 99 vent hole

1469 Views 4 Replies 5 Participants Last post by  BIG ED
Had my type 99 Arisaka out for 2nd time today.
I am reloading for it.
First time out I used 43grn of H4895. Max load is 44grn
OK, no issues first time out.
Today, I loaded 42, 42.5 and 43grn.
About 3 times (I think on 42.5 only) I felt a blast coming out the top vent hole.
The case was a bit carboned at the rim.
I had a hat on and I felt the air hit my rim of the hat. Like someone puffed air at me. Not hard or anything, but I felt it.
Is this typical? Might I have a headspace issue? Or maybe a light load did not expand the brass enough?
I did not see any cracks in the case or primer. The brass is new PPU brass from Grafs.

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Most likely light load, not sealing the brass to the chamber.
You should always wear protective glasses when firing any type of firearm but especially with the Japanese Arisaka's. It is typical to get a blast of gas occasionally no matter what load you are using because of the different chamber sizes and different dimension of various types of brass.
If the case necks are sooty your load is to light. I use 45.0 grain IMR 4895 with 150gr FMJ bullets pulled from .303 British rounds. I only used 42.0 grains in my late rifles.
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