Questions from a 300 Whisper newbie

[Stephen J.]

So, my Model 1 upper is in transit, as are my CH4D dies. I'm going up to a meet a guy that is going to let me use his already set up Dillon 550 to load up some ammo. While I am there he is going to thread my barrels for flash hiders and make me a ram extension and a trim die so I can make my own brass from 223 in my Dillon XL650. That's for a little background. Now for my questions. I currently have ~100 Hornady 220gr Interlock Round Nose Bullets, as well as 200 Sierra MatchKing 220gr BTHP, ~100 165gr Nosler Ballistic Tip Boat Tails. I won't tell you how little I paid for them because I don't want to make you jealous. Anyway, I want to load 2 basic rounds. One high velocity (2200+) with a light bullet and one subsonic with a heavy bullet. Over on the Ultimate 300/221 Page there is an OAL listed for the 220gr RN. Since I have some of these I would like to know what people think of using this bullet and what powder should be used. Are there feeding problems with a round nose in the AR action? I see that H110 seems to be a popular powder, but that it tends to foul the gas mechanism. Thoughts on this? I am going back to the place where I got the above listed bullets to dig through more piles of reloading stuff. What should I be looking for in the way of powder? And finally, anybody have any experience or know anyone who has any experience with the gas piston conversion sold by Centerfire Systems?

Stephen

[Lawfficer]

The 220RN load into the chamber from the mag with no problems.

[Scoots]

I was having chambering problems with 220gr RN's, so I had to use Larry Willis' "split case tool" for determining the OAL of 220gr. RN loads for my Olympic barrel. Ten seperate closures on the "split case tool" resulted in an average OAL of 2.310" for my chamber. I don't have the special attachment on my calipers for measuring from the ogive of the bullet like Larry does, I have to go with OAL. But, I couldn't get this cartridge length to correctly load or feed from the magazine. I had to keep reducing my OAL until I reached a length of 2.010"!!! Now, my RN bullets feed from the magazine and chamber without a hitch.
http://www.larrywillis.com/OAL.html

[Stephen J.]

Well, I have my upper. I loaded three different cartridges. 220gr RN at 12.5gr H110, 220gr BTHP MatchKings w/ 12.5gr H110 and 165gr Ballistic Tips at 17.6gr. I based my charges off of information a friend of mine had. As Lawfficer will probably notice, the 165s were over charged. I'm not sure where my friend got his numbers but the 165 that I fired did pop the primer. I am going to be pulling them and reloading them. Interestingly, neither of the 220s were subsonic. I don't have a chrony yet so I'm not sure what their speed is. I'm looking forward to getting some shooting in. I also have all of the parts to make brass en mass. A friend made an extension shell holder and a trim die from a Grade 8 Bolt for me so I can use my rapid trim. Anyway, got to run.