Help with subsonic load.

[Siringo]

FROM MY POST ON "YOUR BEST PLINKING LOAD".

I will keep this in the current running thread here.

I want to develop a load using the 230 grain jacketed round nose that moves along around 1500 to 1600 fps. I don't want fast -- I want slow.

There was a recent article about using IMR Trail Boss for reduced loadings in rifle cartridges. This powder was developed for Cowboy Action Shooting. The way the article described how to load -- find where the base of the bullet sits in the case and fill the powder to that point. That is the maximum load. Take 75% of that amount -- that is your starting load. Well I did this using 284 cases and Montana 230 gr round nose bullets seated to 2.10 inches. The amount of powder was 14.4 grains.

I shot 5 of these to see if the action would stay open and it did not -- meaning not enough pressure. I have no idea on the velocity. Since that bullet is .4505 diameter, I am going to try with true .452's to see if they makes any pressure difference and try 450B cases because they hold one more grain of powder.

Developing---------------

[wildcatter]

FROM MY POST ON "YOUR BEST PLINKING LOAD".

I will keep this in the current running thread here.

I want to develop a load using the 230 grain jacketed round nose that moves along around 1500 to 1600 fps. I don't want fast -- I want slow.

There was a recent article about using IMR Trail Boss for reduced loadings in rifle cartridges. This powder was developed for Cowboy Action Shooting. The way the article described how to load -- find where the base of the bullet sits in the case and fill the powder to that point. That is the maximum load. Take 75% of that amount -- that is your starting load. Well I did this using 284 cases and Montana 230 gr round nose bullets seated to 2.10 inches. The amount of powder was 14.4 grains.

I shot 5 of these to see if the action would stay open and it did not -- meaning not enough pressure. I have no idea on the velocity. Since that bullet is .4505 diameter, I am going to try with true .452's to see if they makes any pressure difference and try 450B cases because they hold one more grain of powder.

Developing---------------

What were you able to do, to determine that the powder was at the bottom of the bullet, in order to calculate your 75%/14.4gr loading.

And.

If 14.4gr was 75%, did you determine wither or not, if you could go to 100% with safe pressures, in an effort to hold the bolt open?..t

[Siringo]

I have a case (284) with the primer pocket drilled, so a hole into the case is the same diameter as the primer pocket. In this case a large rifle size. Case is loaded with appropriate bullet, to appropriate length and then filled with powder via the primer pocket hole, tapped to insure full capacity, the powder dumped into a scale. 14.4 grains was 100% -sorry, my first description was not clear. 75% would have been 10.8 grains. In a 450B case it was about 1 grain more.

Action would not stay open with 14.4 grains and I doubt one more grain would do anything. Bolt did not even move rearward enough to cause a FTE jam.

I abandoned the idea with trail boss. Good idea for manually operated arms though.

[wildcatter]

I should have known, you are very exacting. So, a slower powder is in the offing. I forget who, but one of the guys is going to try H4831. I've gone the very slow powders before, to get really big bullets to go subsonic, but not our lighter bullets, so these coming loads will be interesting.

For you new guys, make sure you single shoot the weapon, with the magazine IN, as we're looking for the bolt to lock open, to be able to gage success. And, do as Siringo has done to get the exact max loading for you Cartridge OAL and then only use loads that are at least 80% (I think 90% is even better, for that margin of error) of the Max, or more, looking for pressure signs all the while..t

[Siringo]

458 Socom folks use 4198.

[wildcatter]

458 Socom folks use 4198.

Keep in mind they are dealing with a bottle necked case..t

[J-bird]

had a chance to shoot some h4831 this weekend, and crap is worthless. there was so much unburned powder in the lugs that the bolt wold not lock up on the next round. it did cycle the action it would just jam up the lugs on the bolt with crap. I think I'm still gona try some trail boss. any other suggestions of powder i should be looking at?

Does anyone have any experience with Accurate 2495. looks to be a good candidate to me but I have no experience with it.

Thanks

[Siringo]

Doubt trail boss will work the action -- it did not in mine. Your experience with H4831 is the same as I got with 5744. Although, that powder worked the action and velocities were in the range you are seeking. However, lots of unburned powder. I have used this powder in 45LC and 45-70 with the same results of unburned -- although it is very accurate.

[Siringo]

What about H4227 or IMR 4759? Someone needs to run these on Quick Load.

[BD1]

I can run them on quick load if you give me the parameters: COAL, bullet length, and the particular bullet if it's in the data base.
However: The database Quickload uses for the .450B is based on the single Hornady factory loading, the farther we get from that, the less valid the Quickload results will be. All of the subsonic loading parameters are pretty far from the basis used for Quickload.
BD