300-mp

[Blammer]

Ok, it's a fairly new powder on the market, who has experience with it.

I'm fixin' to get a lot of experience with it as I have 2 8lb kegs of it now.

Just looking to see what you think of it and how and what you use it in.

I see they state that with 29gr and a 200gr jacketed bullet they are pushing 1700 fps in a 44mag.

[MarkP]

I have used it in 44 mag; 7-1/2" RedHawk, 10-1/2" BH, Rem 788, Rossi Puma. I shot some over the chronograph and the numbers were close to published data in the Red hawk; The 310 gr Lee in my 788 shot in the mid 1,600 fps and I think 240's were in the 1,800 fps range.

Seemed similar to H-110 / 296; I shot these when it was pretty cold out single digit temps (F) not sure how velocity would compare with 110 / 296. The handguns had a little bit that day due to the cold temperatures, I forgot my gloves.

Used in my 221 FB with the 225107 HP & FN.

[pkie44]

Near max loads with heavy bullets and long barrels makes it shine. No need for mag primers.

[leadman]

I loaded in my 41 Ruger SBH Hunter with 220gr TC and SWC. Just a bit slower in burn rate then 296 as I had to load a couple grains more to get the same case expansion. Velocity was close to 100 fps higher with 300MP.
I also loaded in my Mosin Nagant and got the best accuracy ever with it in that gun.
Does have a very loud "BOOM" compared to Lil Gun in my 41.

[blaser.306]

I shot 300-mp in my 445 super mag using the " it is close to 296 / 110 idea " started ladder test loads low and worked up. First round down the pipe and I had to beat the brass from my contender? Alliant was less than helpful when asked about any " pressure excursions " I still have the rest of the lb somewhere so will be watching with interest.

[tja6435]

I've noticed that it's beginning charges are right around max charges for h110/296. Once you get towards the top end of the 300-mp load, it'll begin burning nice and clean. Below that optimal pressure, it's not near as clean burning but still works well. I have multiple kegs of 300-mp for .357 and 44 mag loads. I like it, I like the price of it as well. Much cheaper than any other magnum powder I can find.

[Elkins45]

I'm experimenting with it in 300 blackout with heavy subsonic loads. Burn rate in that application seems similar to 2400 IMO. It and IMR 4227 are currently auditioning to be my subsonic black powder to fill the gap until 2400 returns to the market. I can't say with any certainty which one is best just yet.

[tja6435]

I've picked up 22# 2400 within the last 5-6 weeks. It's out there but you have to pursue it to obtain it. I passively looked for it for 5-6 years with no luck (same thing with Blue Dot, passively looked since before Obummer and just recently got a couple lbs), once I began checking several powder distributors several times daily I finally ran into some at Ballistic Supply. Wideners had kegs of 300-MP for $117/ea.
I have an outstanding order for 24-50# of 2400 with my local powder distributor, but he does not expect to fill it any time soon, if ever.

[abqcaster]

In 357 magnum, I use it near max under a 158gr Remington jacketed soft point. It's super accurate out of a Ruger 77, at 1,980fps. Burns pretty clean too. Haven't shot it in low light but I haven't had any issues with muzzle blast or smoke in the daytime. Under a 125gn XTP I get 2200fps, near max loading and good accuracy. (also, both loads use Win SPP) YMMV...
-ABQ

[leadman]

blaser 306, I also asked Alliant about pressure excursions and if it was restricted to a 3% reduction from max load like 296/110. Silence was all I got on the line.
I have seen on other forums that some think it is 297 powder.

[Blammer]

abqcaster, what cartridge are you shooting?

[MT Chambers]

It is being used in small shuetzen type cartridges such as the 25/20 SS and 32 miller, etc. Reduced loads giving good accuracy.

[abqcaster]

Blammer .357magnum.

[Blammer]

thanks, think I'll give it a go in my 360 DW.

[427smith]

I've been working on 300 mp in my 450 bushmaster ar15 with 20 inch barrel. Before it got warm enough to set my chronograph up I thought I had good results. But, chronograph shows extreme fps spread to be 200 fps. More powder equaled more velocity and a cleaner burn but didn't help spread. so I contacted Alliant. NO help. Quote "(no tested data for the 450 bushmaster let alone for cast bullets, Lyman cast bullet handbook 4th edition lists no data either)" I was surprised Alliant referred to Lyman. guess I'll proceed on my own. Let you guys know if I figure it out.

[ripshod]

I am interested in using this powder in my 357 maxi Handi rifle.I have some 360 DW brass and a couple of hundred Maxi brass.I am thinking about starting with the DW brass with a charge a bout 2 grains above regular 357 data.Anyone have any ideas on this?ripshod

[leadman]

I would start lower and work up. If I was doing it I would start a grain or 2 above 357 mag starting loads and work up. Guns, primer, cases, and bullets/boolits vary and have seen times when pressure signs were reached well before published load data.

[Blammer]

anybody have any load data? all I can find is from Alliant and they list ONE powder charge. Is it the middle of the road or Min or Max they don't say.

anyone else have any data?

[ripshod]

It seems that I recall that someone that posted under the name 357 Maximum mentioned using this powder in the .357 maximum with success.I don't recall any specific load data.ripshod

[donhuff]

ripshod,

I loaded some 300mp in 360DW. I modified my Rossi 92 to take the longer cartridge once Starline finally made the brass and I had it in hand. I had been wanting to do this for a while but wouldn't until I knew for sure that the brass was available.

I started loading @ 19.0 grains to be safe, but that was way to low. This was loaded behind a magtech 158 JSP, and things did not really start sounding and looking right until I got the load up to 21.0 grs. At 22.0 it was looking real good and I was getting 2010 fps. This is from my 16 inch barrell. Accuracy was good enough to at 3+ inches @ 100 yds. Remember it's a lever gun so 3" really is pretty good. Primers and extraction were ok with the top load so I'm sure there is a little more left to go,I did load a few at 22.5 and 23.0 grs but did not get a chrono reading on them, bad lighting or something. Primers and extraction were still fine, but there is no room left in the case for more powder as this is compressed a bit. Then for some reason I jumped over to LilGun powder and did not go any farther with the 300 load. I need to try it again and see where the top limit is. See my full report here bout midways down the page. http://www.rossi-rifleman.com/viewto...=4436&start=50

And then I jumped up to a 180 grain cast bullet and 300MP. I am using the NOE 358-180 (BRP) bullet. I think I got it up to 20.0 grains and 1975 fps, before I saw a little flattening of the primers, and so I backed it off to 19.5 for a max load with pretty good accuracy. again more details here http://www.rossi-rifleman.com/viewtopic.php?f=20&t=4542