I'm reloading for a Ruger 77/44 with an integral suppressor.  I think it has an 9" barrel in there somewhere.  Reloading with new Starline Brass trimmed to consistent length.  Using Lee Carbide 4 die set.  Loading 300 grain Nosler Sporting Handgun pills, as the 300 grain XTPs act as a FMJ at 1050 fps, and I don't want to go any faster than that.  I sent a couple of the Nosler SH bullets to Lee and they sent me a custom seating plug- it deforms the front of the soft lead a lot less than the original plug, but still getting deformation.  I know the jacket on thees is very thin, and have blown a few apart with inertia hammer puller.  

My questions-
1) other jacketed 300 grain bullets that reliably mushroom at 1,050 or slower?  Need to be jacketed due to the suppressor.

2) other seating dies that are better designed to seat JHPs with no deformation?  

3) While we're on the subject, I am in the process of getting set up for reloading 45ACP that will also be shot though a suppressor, so same requirements of sub-1050 fps velociy and a jacket.  I have not purchased dies yet.  I do have a couple hundred 230 grain Gold Dot pulls that I am going to do the first run with.  Would like some recommendations on die sets for them.  

Oh, and if it matters, am currently loading on a RCBS single stage, but have a 550B en route from North Pole.

I would see if the various bullet manufacturer's make a bullet designed for the 44 Special.

As for the seating deformation.... make sure you crimp in a separate seat... do not seat and crimp together.

It is possible the crimp is interfering with the seating step.

.45 ACP... if you are going to use the Gold Dot bullets... I am pretty sure RCBS make a specific seating stem profiled for the various GD bullets.

The problem isn't the dies. Pretty sure it's the brass. Starline is thicker than WW or RP. I had the same problem with Hornady dies and  240 grain XTPs, and 240 Sierra JHCs.

M die

AM using the Lee FCD in a separate step, so no interference there.  I think I no longer care about the slight deformation of the tips- found that Starline brass trimmed to 1.270, over 18.4 grains of IMR 4227, seated to 1.610 and crimped with 1 full turn gives me an average of 1,066 fps at 30 degrees with an extreme spread of 16 fps and a five shot group at 100 yards of 1.1".  I will freaking take that.

As to the 45 dies, I think you are correct and will likely go that direction.  

THanks to all for the input.

Not everyone has a lath available.

I have turned many M die 'plugs' since the lath is kept around for other tasks.