223 mini 14 working up loads

[jb]

with bolt guns for hunting i find a big differance in max. loads. i have 15 to 20 reloading manuals and they show the same differance. how do i read presure on this gas gun? i use a .0000 mic. and bolt lift on bolt guns but don't know what to look for with a gas rifle. thank you.

 

[Mikem]

You dont have the latitude when loading for a gas gun that you have with a bolt gun. I would recommend getting a load book for the Mini 14 only, if you can find one, try Google. If not the Sierra reloading book (you must have it if you have 15 to 20 books) has a section on loading for gas guns. And you will want to FL size all your cases, and keep your pressure in the recommended range. Checking pressure are the same, look at you primers first. That's just how it is with gas guns, I have several.
Mike.

 

[Clark]

223:
18 gr Blue Dot 33 gr Vmax moly is erratically from 4100- 4200 fps, 75 kpsi - 85 kpsi.

This load will not cycle an AR15 gas gun.
The [pressure][time] product is too small to push the bolt back far enough for ejection.

There is low noise.
The bolt carrier does not move much.
But the chrono and the brass show that something is going on.

What does it all mean?
Cycling the action is a longer time constant than deforming brass.

 

[infantrytrophy]

Reloading for gas guns is quite different than for bolt guns. The following site has .223 reloading information for ARs. Should be similar to the mini-14, if you stick to the info for the lighter bullets. I have been told that the barrel twist rate is 1-9, so bullets in the 50 to 69 grain range should be good.

If you scroll down to the topic "PRESSURE, EXTREMELY SIMPLIFIED", there is a brief discussion of pressure signs with helpful pictures.

Link: http://njhighpower.com/cart_tech.htm

One caution: be sure to full-length size your brass properly - not too much or too little. Depending on load factors, the brass can be stretched as it extracted under pressure. You can't just "bump" the shoulder back a couple of thousandths, like you do for a bolt gun. The fired case headspace might be longer than the actual chamber headspace. On the other hand, if you size the brass too much (bump the shoulder back too far), you will over-stretch the brass on the next firing and be at risk of a case-head separation. This happened to me on the second firing with excessively-sized brass.

Randy Sikes

 

[Mikem]

I have, and reload for an M1A (M-14) 7.62mm (308?) and use special military grade primers to minimize the possibility of having a slam fire.
I'm not sure if the receiver on the Mini 14 is susceptible to having slam fires or not, or if they make and sell a Military grade SR primer for the 5.56mm (223) case, but if it is, and they do, I recommend it.
You might check a Mini-14 or AR web site about this.
Or someone more knowledgeable than me about this may chime in.
Mike.