Pressure VS seating depth

DsrtRat

DsrtRat

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I just tried some 65 gr bullet sout of my .223 REM 700. They shot ok but noticed the primers looked different after shooting them compared to my 50gr bullets. The dent made by the firing pin is deeper than my lighter bullets and has a moon crater look to them with a small ridge aroun dthe hole. I am guessing that the pressure might be getting up there.

Non of the brass showed any signs of pressure such as cracking, deforming, flattened headstamp, imprint of the bolt head or head sizing growth.

I did make these bullets a little longer after measuring several in the gun to confirm I wasn't into the rifling. Most books recommend 2.20-2.250 OAL. These bullets were 2.331 OAL. My question is, if I make these shorter, will the increase in free-bore decrease the pressure or will the pressure increase due to the decrease in space within the case?
 
Unless the bullets are pushed into the rifling shortening the OAL will not affect pressure, you can check this by taking an uncharged, unprimed case and smoking the bullet and chambering it to see if it contacts the lands. It could just be your 65 gr load is abit warmer than the 50 gr load.
 
Rem's have a notoriously large firing pin hole and will crater the primers quite easily. Unless the brass starts to flow into the ejector hole or the primers are unusually flat you should be ok.

What powder are you using and what amount?
 
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If you are changing from a compressed load to an uncompressed load by increasing OAL, pressure will increase.

If you are contacting the lands whereas before you were not by increasing the OAL, pressure will increase.

If you are using a ball powder and the case is substantially empty, pressure _may_ increase.

Otherwise, pressure will decrease.

This is for the same bullet/powder/charge combo. If you also change out the bullet, all bets are off. Try changing one variable at a time and see what happens ;-). Try seating the 50s to 2.331OAL
 
I am planning on shortening the OAL and seating the bullet deeper. It it already a compressed load so in theory it will be more compressed.

I am using 26gr Varget. All the manuals have 26.4gr as the highest amount to be used and pressure max is around 53,000.
 
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