300BlkTalk

147 tracer would have compressed the powder 1/2 inch

ShortBarrelShepherd wrote:

Ring wrote:tried 17.5gr of 300mp
8" CMMG barrel
with a 147gr Traicer "HOT!!!".. flat primer with some firing pin hole pertrusion ---(WAY COMPRESSED)
and with 150gr copper plated FP's
http://www.xtremebullets.com/308-s/48051.htm
"HOT".. flat primers, no protrusion...

That's very interesting that you had flat primers at 17.5. I ladder up my 147gr M80 pulls to 17.5 and only experienced very slight ejector swipes. I backed down to 17.0 but didn't see the same out of my 6.75" barreled AR15.

Good reason we test our stuff out! What's your lot number on the 300 MP?

I doubt the powder lot number has much to do with his pressure signs.........the Tracer rounds are long as the rear end is filled with light weight burn material.......a long projectile will compress the heck out of the powder charge....300 MP does not take well to compression.

Well I guess you guys answered the question I had about how much compression 300-MP will take before the "Bootleg Fireworks" effect takes over or at least close to it. 1/2 inch is more than I thought you could do with that powder and still type about it.

Alien wrote:"Bootleg Fireworks" effect takes over

GET THA WATER!

Thanks to everyone for talking about compression, I obviously didn't think about that and the length of the tracer projectile.

Out of curiosity, did you have a chrono on those 17.5 gr loads? I bet those 147 gr's were cookin in more ways than one.

Finally had a chance to do some loading today I started out with my 125grain Sierra pro hunter spitzers for now until I'm more comfortable with loading I don't really want to go much outside of published data yet. I used the same data that Powder4sale got from alliant which I also received after emailing them before I had seen it posted on here. I'm thinking about working up to 20 grains if this load runs fine in my gun. With the 19.6 grains the bullet was not compressing the powder at all, and it fills the case very nicely the powder was at about the neck I think a longer boat tail would possibly compress the load. Will report my findings when I get some time to shoot. Also to add I added a crimp to the loads after I finished.

Post range update. Ran some of my loads 125gr Sierra Pro Hunter Spitzers at 19.6 grains of 300MP with an OAL of 2.000 5 shot groups are decent at 100 yards haven't fine tuned my scope yet as I ran out of the 125's (didn't bring enough with me), and had to switch over to slower 150's zero pressure signs no swipe marks from the ejector. Had five loaded a little hotter with 20 grains had a very good report noticeable increase in recoil again same OAL just added .4 more grains all 5 cycled flawlessly very light ejector swipes although the 150's I shot also showed the same swipe. I'm thinking I have some more wiggle room with these due to my lack of pressure signs at 20 grains thinking maybe a few at 20.2, and a few more at 20.4. I goofed and purchased remington 6 1/2 small rifle primers but tried them out anyways I had five loaded with WSR primers the other 20 including the 20 grains had the Remingtons. All of the primers went bang no FTF, and did not have an issue with the primer putting marks in the bolt face. Sorry no chrono data as I do not have one yet but will be getting one fairly soon. Alliant claims 2187 FPS with the 19.6 grain load which I listed above so 2200+ is very feasible with 20 grains if in fact the speed alliant provided is correct. As per the norm these worked for me with my rifle.

Not sure if you have seen this, or how new it is, but Nosler updated their info. They now show a load for their 125 grain bullets and 300 MP. Seems to be running close to what others have found and posted that it takes about 1 grain more to reach H110/296 velocities. They show 19.5 as max load with a density of 108% at 2240 fps.
http://static.squarespace.com/static/51 ... ormat=750w

LOL, who wants some 300MP?