Different Brass Prep For Different Loads?

Perkules · #1 03-15-2004, 04:35 AM

Well now I got thinking... [img]images/icons/confused.gif[/img]

First of all, I usually have just one load for one rifle, this is a new situation somehow so please bear with me if the answer is all too obvious for you more experienced people.

I have a large chamber in my 338 LM. One load with 300 SMK:s gives me brass that is very easy to resize. Another 225 SST load is a hotter one and the cases expand a tad more, easy to feel the difference when FL sizing, which I´ve been doing until now.

Now,should I keep the brass for each load separate? I just partially sized a bunch of brass for SST:s for a snug chamber fit (and to minimize brass work) and realised that if I load 300 SMK:s with this brass my load won´t be the same anymore. The 300 SMK load doesn´t actually fully expand the brass to the chamber dimensions, Lapua brass is tough - and the TRG-S chamber is huge, I suppose.

Or maybe just K.I.S.S. and keep on FL sizing it all for simplicity? I´ve been miking stuff like crazy all day, can´t decide.

I may get the answer today though, going to see how the SST load works now ,it must have changed as well because of the change in sizing process. There´s no telling of the uniformity of this chamber either, not with my tools so all I can do is go shooting and hope to see some changes. [img]images/icons/grin.gif[/img]

Thanks!

Perkules · #2 03-15-2004, 06:40 PM

Hard to tell, it was windy and raining.

I got some repeated 0.8"/three shots at 100 meters though but everything got soaked and the low 30´s took my concentration away so my shooting went out the window. Couldn´t chrono either.

SST load still under construction. I´ll stick to the chamber dimensions now, the fired brass came out the chamber without problems,looking very clean. No L/R POI difference compared to SMK:s. [img]images/icons/smile.gif[/img]

Factory Scenar loads (and my 300 SMK) look dirty at the neck ater being fired.

[ 03-15-2004: Message edited by: Petander ]

Dave King · #3 03-15-2004, 06:52 PM

Petander

You talking to yourself?? Must be those winters!

I believe that I'd not mix the brass, can't state why just a gut feeling.

Perkules · #4 03-16-2004, 03:12 AM

Yeah it´s the weather. [img]images/icons/grin.gif[/img]

Me agreed with myself on the matter: We´ll just fireform all our brass using the SST load. MatchKings may like that too, must try some first.

I wonder why the SST:s give so much more pressure though, MK load is supposed to be hotter according to the tables. Same powder and .010" off the lands.

Dave King · #5 03-16-2004, 03:27 AM

Petander

I don't know much about the construction of the SSTs. Are they monometal, thick harder(ened) jacket, or perhaps a "partition".

I've found that some bullets either being a little larger (.3082 compared to .3079) or "thougher" contruction will increase pressure as they resist the engraving process a little more.

FWIW

Perkules · #6 03-16-2004, 04:37 AM

SST:s are just tough bullets, maybe too tough.

Their diameter is slightly smaller than MatchKings, about 3/10 000 as far as I can measure. Must be the jacket material, whatever that makes for the "toughness", they should penetrate good but I have no idea of , say, 400-500 yard performance on moose.

Matchking may be much better - and the weight alone makes it my choice, not to mention other ballistics and accuracy. 500 yard newspaper comparision to come one day, just for the heck of it. Some authoriries are possibly going to classify MK:s as FMJ:s over here... that may mean trouble so it´s good to have two loads. [img]images/icons/rolleyes.gif[/img]