Finally...time to test the 375 rum and the 320 ce

[benchracer]

The mouth of the case is right exactly at the band. So if I here you correctly, I should seat the bullet further into the case making it shorter coal. Correct?

That depends upon how far the sealtite band is from the rifling. If you start at .020 or so from the rifling and back it off another .120 or so, that should put the sealtite band (and the bullet) deeper in the case at some point. The CE tech gave a couple of examples of load development he had done where the MTH's shot better with the sealtite band seated into the case neck (I believe CE guidelines say to seat the sealtite band no deeper than half the length of the case neck). Of course, it's hard to know if they will behave that way in your rifle or not, but it may be worth checking out.

If your rifle shows a preference for deep seating the CE's, IMR 7828SSC could show an advantage with its lesser bulk vs RL-22.

 

[benchracer]

Here is what Ken Kempa of CE bullets had to say in response to my questions regarding finding optimum seating depth for MTH bullets in a .375 H&H:

Normal starting point is the SealTite Band™ just above the end of the neck. From that point you can lengthen in .030 or .035" increments- normally not very sensitive at all to seating depth. OR you can seat the SealTite Band™ into the neck, up to one-half the length of the neck (or about .170" below case neck end).

I worked up a great load for a 100% stock Steyr ProHunter in .270 Win. Using our 115 Copper Raptor (smooth body, and SealTite Band™ (STB) just like our MTH bullets) and H4350, I was repeatedly getting ½" groups at 100 yards. Then I had to do some ammo for a TV show in CA. My loads were at 3.400" OAL, but as I did not know if their rifle would accept it, so I deep seated the STB inside the neck, with a new OAL of 3.340". When I shot them I got this actual sub .250 group! So no… they are not "fussy" as far as seating depth.

 

[Doublezranch]

So maybe I will do one group with the band just inside the neck and do a second maybe 10-20 thou outside the neck and see what happens. It's not like these bullets are expensive!! LOL!!!!

P.s......I just ordered 2 more boxes....

 

[benchracer]

So maybe I will do one group with the band just inside the neck and do a second maybe 10-20 thou outside the neck and see what happens. It's not like these bullets are expensive!! LOL!!!!

P.s......I just ordered 2 more boxes....

If you are satisfied with the results you have obtained, there is not necessarily a need to go further. It all depends on what your goals are and whether or not you have met them.

 

[Doublezranch]

I sure would like to tighten up that group if possible. Certainly the velocity is very exciting. I'll play with seating depth after the 7828 ssc ladder. No matter what happens from here, I think we all agree we are on the right track!!

 

[Tikkamike]

seating the band in further than flush with the case mouth is hard for me to grasp... thats going to mess with the neck tension and anything infront of the sealtite band will just be open.. am i picturing this right?

 

[Doublezranch]

I think so. That band as I have it now is perfectly in the center of the case mouth. I'm skeptical about pushing it further into the neck. Also, I'm nervous about having too far away from the neck. Let me go a thou longer and shorter and see where the band ends up.

 

[Tikkamike]

text me some pics if you think of it while you are playing with it

 

[MudRunner2005]

Oh my gosh I forgot the pic. Here she is next to a 300 win...

I don't really care for the big bores, or the huge overbore magnum ultra-mag Lapua and .404 Jeffery type cartridges, BUT, that looks to be about on the same overbore scale of a .30-06 AI......And QL shows that with a 26" barrel that 7828 SSC is the optimal burn powder.

Therefore........I like it! And it looks nasty.

 

[bigngreen]

I've had very good luck seating the seal tight band just of the case mouth, finding my best charge and then I'd it needs tweeked I seat them out .010 at a time. Touching the mouth opens the group and seating into the case blows my groups up in every thing I've loaded the CE in.

 

[Doublezranch]

So if I here you right Rhian, the farther out you seated the bullet, the better your groups. The more you pressed the band down into the neck, the worse accuracy you achieved. Did I get that right?

 

[HARPERC]

If it works out, there a Wyoming antelope with its name on one!!

Now I'm confused, you've got 260 Accubonds for bear hunting, and the 320 CE for antelope. Hammer them both with the 320.

 

[Doublezranch]

Ok...ok...Harp I agree with you. I knew the 320 ce bullets were going to take a little tweak so that's the reason I bought the 260 accubonds. I knew I could get the accubonds to shoot the first day at the range so that's my logic. I wanted to have a bullet ready to go for sure and have completed that mission. However the work up on ce's is going unexpectingly good so I might just roll with them!!

 

[Tikkamike]

All this 375 talk is making me jealous, I sent mine in to get pillar bedded and in the mean time bought a Nightforce and new mounts for it...but its not back yet and I am getting ancy!