Chamber Pressure Info
 

Anyone know where I can find any data on .300/.221supersonic load chamber pressures?

You may need to be more specific. The RCBS QuickLoad program may be what you want.

If you are using 223 cases, they are good for about 50kpsi.

Just trying to find out if where .300/.221 17 gr of h110 with a 147gr fmj might be on the scale in relation to pressures generated by moderate .223 loads.

According to Quickload, that 17.0 grain load at a 2.250" COAL generates a little under 43000PSI. At a COAL of 2.200" (what I load to, I think that's just under the cannelure) that same load would generate over 54000PSI according to QL.

In my experience with the lighter bullets (110 & 125), I've experienced high pressure signs with H110 in loads that QL estimates at 39-40000PSI. I switched to AA1680 for all loads, and have had great luck with the 147 grain bullets at 2.200" COAL and working from 16.0 to 18.0 grains of 1680, outstanding accuracy with almost all loads.

Your 17 gr H110 are max loads. Here is the reloading data for 150 from bullets from the Sierra reloading manual.

These loads were developed in a 10-in barrel TC contender. A 16-in barrel will produce about an additional 200 fps.
C.O.A.L. 2.25
Powder /Velocity 1400--1500--1600--1700--1800
AA-No.9 ----------12.4---13.4--14.4--15.5
2400 --------------13.4---14.1--14.8--15.7
Viht N110---------11.8---13.0--14.2--15.4---16.5
H110 ---------------------13.8--14.8--15.9---17.0
296 -----------------------13.8--14.8--15.9---17.0
Viht N120 --------15.1---16.3--17.5--18.7
AA-1680 ---------14.7---16.0---17.4--18.8

320pf

Thanks for the responses guys. pomofo, that is some good info. Looks like I should get quickload on my P.C. I am done messing around with max loads & H110. I did pick up some AA1680, & will give that a go. I think my M1S chamber allows me to seat to 1.185". I understand that quickload is not a precision tool.