Cartridge length question

[KenC]

I am handloading for a Thompson Compass 300 Win Mag BA rifle. I am using 225 grain Hornady ELD-M bullets in front of 74.7 grains of H1000 and a CCI 250 primer. S'posed to be OK in my 10:1.

The consensus is that best consistency results from the ogive being .020" off the lands. I get this with a COAL = 3.642". The longest cartridge that fits the magazine has COAL = 3.476". For reference SAAMI max COAL = 3.340".

So, I am relegated to hand feeding the beast.

Are there any rifles with longer magazines and actions to accommodate these newer long bullets? I only need 0.17" (3/16) more than I have.

Ken C

 

[CarJunkieLS1]

If you want to run a magazine then set them at max mag length and shoot them. That way if it doesn't shoot well you can only go one way.

 

[climbnjump]

The consensus is that best consistency results from the ogive being .020" off the lands.

But that might be the consensus for rifles that aren't yours.

If you want to run a magazine then set them at max mag length and shoot them. That way if it doesn't shoot well you can only go one way.

Yup, this. Give it a try. You have nothing to lose except a few bullets downrange.

 

[LoonWulf]

I agree, try at max mag length.

There are plenty of action that have longer mag boxes, the most common being the 700 and derivatives. They will take 3.7" or so.

My .300s only got a 3.43" magazine, and a similar distance to lands as yours.

 

[jmr40]

I always load to fit the magazine. That almost always gives me good accuracy.

 

[Varminterror]

Are there any rifles with longer magazines and actions to accommodate these newer long bullets?

Seekins Havak. Their proprietary mag boxes accommodate something over 3.9xx”

 

[KenC]

If you want to run a magazine then set them at max mag length and shoot them. That way if it doesn't shoot well you can only go one way.

Only problem is I am hearing a little crunch from the H1000 while seating the ELD-M's at max mag length . . .

 

[climbnjump]

I am handloading for a Thompson Compass 300 Win Mag BA rifle. I am using 225 grain Hornady ELD-M bullets in front of 74.7 grains of H1000 and a CCI 250 primer. S'posed to be OK in my 10:1.

The consensus is that best consistency results from the ogive being .020" off the lands. I get this with a COAL = 3.642". The longest cartridge that fits the magazine has COAL = 3.476". For reference SAAMI max COAL = 3.340".

Hmm... SUPPOSED to be OK? Ultimately it might end up being just fine, but...

Only problem is I am hearing a little crunch from the H1000 while seating the ELD-M's at max mag length . . .

Yes, even loading to 3.476", that load is a compressed load.

If you were to load to SAAMI spec COL, that load would be over pressure.

It's pretty close to MAX pressure even loaded to 3.476" so you might consider backing off a few grains to start.

 

[Captcurt]

Just because it is a long jump to the lands doesn't mean that accuracy will suffer. I know my Weatherbys were long throated and I've had 2 that shot very well when seated to fit the magazine.

 

[bfoosh006]

Only problem is I am hearing a little crunch from the H1000 while seating the ELD-M's at max mag length . . .

Have you tried a powder drop tube ?

And FWIW.. you might find these articles about bullet seating / OAL interesting

https://precisionrifleblog.com/

 

[CarJunkieLS1]

H-1000 IME tends to shoot better if it a little bit compressed. If you are within published data and your bullets aren't getting damaged from seating them, or the COAL isn't growing then you are doing just fine.

I second, using a drop tube or giving a little tap to the sides of the cases while you pour the powder in.

 

[Varminterror]

Just because it is a long jump to the lands doesn't mean that accuracy will suffer. I know my Weatherbys were long throated and I've had 2 that shot very well when seated to fit the magazine.

There are also a lot of folks who have struggled to get Wby’s to shoot, or some of the era of long throat REM’s. They were generally a higher grade rifle so they could outshoot the rack standard Win’s and Rem’s of the day, but a lot of folks have been rankled by the long throat Wby’s. I still occasionally have folks being Wby’s to me for help in load development, and I always have to calibrate expectations.