New 300 Whisper

[gds]

I should have my .300 whisper barrel today and I am trying to decide on the loadings. My main projectiles will be 125g Soft point for super sonic and a 200g cast round nose for sub sonic. The barrel is 16.25", gas port in the carbine position with a JP adjustable gas block, and 1 in 10 twist.

The load data seams to be all over the place so I figured I would ask for some good starting loads from the guys here. Here are the powders I have available that I have seen listed.

Blue Dot
Red Dot
Reloder 7
AA 1680
2400

I will also be doing some 120g and 155g cast super sonic.

[snipecatcher]

Red dot is too fast. 2400 is very close to VVN-110 on the burn rate charts, and should work pretty well, though I have not personally tried it yet.

[Fritzcat]

Look at Sierra Load Data. I use Blue Dot for my Sub Sonic 150gr to 180gr bullets, but is too hot for 200gr and heavier.

[TCCrewchief76]

I'm goinh to be using the RCBS 309-200-SIL bullet in my whisper for the subsonic stuff. SMK's are just ridiculously priced. I get a projo of around 215 grains when cast of straight wheelweight. The round has a small meplat on it, so I wouldn't hesitate to use it for hunting hogs either. Of course the cast bullets build pressure much gentler than jacketed, so some additional load tweeking will be necessary. I'm in the process of building a suppressed AR, so when I have data I'll be sure to share.

Kevin

[Jerryr98]

I have had my Remington 700 based 300/221 for about a week until I screwed it up. I loaded 50 rounds, I weigh each charge, inspect my cases (powder level in the case) after all are charged and again as I go to seat the bullet. So after following Sierra's reloading data and firing 40 or so rounds, why did I blow a primer and send powder residue and muzzle blast/noise back in my face? I even pulled the bullets on the remaining loads and each measured exactly 10.7grs which is a low end starting load with Sierra's 200gr MK straight from the Sierra maunual. So now my new rifle has a screwed up extractor and my gunsmith wants to examine the rifle for any defects (other than the extractor, that's an obvious issue). But here's the kicker, since building mine he has built two AR based 300/221's. One functions fine with his H110 loads and the other has done the same thing to him that my bolt gun did? Even baffled him??? So I begin researching 300/221 loading issues. After reading of some issues on quarterbore from fellow whisper shooters I have formed an opinion that H110 should be avoided. Take a look at the one post titled KABOOM! While my mishap was not to that extreme I still find myself being gun-shy and lost as well. What the hell is going on? Sure seems to be a link with the H110 and the whisper cartridge and it doesn't look good????

[Scalce]

After reading of some issues on quarterbore from fellow whisper shooters I have formed an opinion that H110 should be avoided. Take a look at the one post titled KABOOM! While my mishap was not to that extreme I still find myself being gun-shy and lost as well. What the hell is going on? Sure seems to be a link with the H110 and the whisper cartridge and it doesn't look good????

Is it possible that since the majority of people starting out loading 300 Whisper use H110, it may be a coincidence that H110 was involved in the three examples you cite?

It's also alittle suspect that both your bolt gun barrel and an AR barrel that the same gunsmith made have both had issues but I guess that could be a coincidence as well.

I'm interested to read about any other issues with H110 as I currently have some loads with it I am testing.

I also have 2400 and #9 but I haven't got that far yet.

I think loading a wildcat with fast powders and heavy bullets does not leave alot of margin for error with new reloaders.

I am not saying you are a new reloader but I bet that does play into some part of the equation in some cases.

[3006mv]

aa 1680 good for cast 200

[Seddo]

I am using AR2205 (H4227) for super sonic loads with 155's and subsonic with 208's in a bolt gun and pump. I was working up loads in my 338 whisper before i sold it (biuilding a pump this time).

[3006mv]

Reloader 7 is also good