Just received my 300 gr. gas checked bullets from Beartooth. Noted in Loadswap only one load using Speer bullets. Is it possible and safe to work up a load using the load data for the 290 gr.listed in the forum?
What powders do you intend to use? I have experience with several powders and 300 grain cast in the .444 to include: WW680 (supply exhausted), IMR 4198, AA2200, AA2015, Re7, H322, mil-surp 8208, IMR 3031, H335, AA2230-C and mil-surp 4895. In my opinion, the first one is too fast, the last two are too slow and 3031 is too bulky; therefore, that leaves at least a half dozen powders (there could be others!<!--emo&--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=''><!--endemo--> I feel work well with 300 grain cast in the Triple Four.
I'm not very familiar with the features of this sight but I read your reply in "my folder"... I guess that's what it's called.
Anyway, I noticed you have Re7 and H335. Re7 is probably one of the best .444 powders out there and a good healthy starting load is 41 to 42 grains with a 300 grain cast (approaches 2000 fps from an 18" bbl). H335 is another good .444 powder, especially if you have a 22 to 24" bbl. However, I don't really care for it in the short ported bbl of the Marlin 444P due to excessive flash and report. Nevertheless, right around 55 grains of H335 will get your 300 grain cast bullet moving near 2100fps from an 18" bbl. Actually any of the extruded powders I mentioned earlier can be used at about 40 grains to start and worked up until you get pressure signs or until your case volume is "maxed" out. One thing you may or may not know already is that pressure signs for a lever action rifle are more subtle than a bolt action. The reason for this is due to the fact that brass doesn't start to "flow" until pressures hit about 50K which is above the safe limits for all lever guns sans the Winchester "Fat Sides". Therefore, the best tool for measuring pressure is the chronograph mated with the micrometer. When checking your case head expansion with a micrometer, compare the expansion of your handloads to that of factory ammo shot in your rifle. When you're shooting your stuff through the chronograph, retest any loads that show more than a 100 fps range and especially take heed of those 10 shot strings that produce odd ball readings; e.g., one or two shots which are 50 to 100 or more fps higher than the average for the string. I should probably also mention that the ball powders produce average velocities that can vary somewhat depending on ambient temperatures... which is another reason why I like Re7, AA2015, 8208 and to a lesser extent IMR 4198 which is a tad too fast for the 300 grainers and meters somewhat harder than the others. Unfortunately, I haven't had the opportunity to try Short Cut 4198 yet. Oh yeah, I almost forgot about AA2200. AA2200 is very similar to H335 in the Triple Four but is a bit faster burning and charges should be a couple grains less. It does however deliver velocities within 100fps of H335 and if you can still find it, it's very economical.
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