"Max effort" 300 Win Mag

[buckbrush]

With the introduction of the 230 SMK and the planned introduction of a 245 Berger, I was considering a new 30 cal build. Rather than going to something requiring a 0.590" bolt face I thought I'd take advantage of all of my on-hand 300 Win supplies and try a reamer with longer freebore than the SAAMI spec reamer I have been using. I'd probably use a long 9-twist barrel...maybe 30".

Any speculation on velocity with the 230s? Does anyone feel this will be a lesson in futility?

 

[dkhunt14]

Maybe 2800, with a slow powder. Matt

 

[LA50SHOOTER]

W

With the introduction of the 230 SMK and the planned introduction of a 245 Berger, I was considering a new 30 cal build. Rather than going to something requiring a 0.590" bolt face I thought I'd take advantage of all of my on-hand 300 Win supplies and try a reamer with longer freebore than the SAAMI spec reamer I have been using. I'd probably use a long 9-twist barrel...maybe 30".

Any speculation on velocity with the 230s? Does anyone feel this will be a lesson in futility?

What is the goal as far as accuracy & velocity ?
If you have Quick-Load you could probably adjust the desired parameters and get a "ball-park" idea what to expect at what calculated pressures.
How well either of the 2 named bullets will shoot accurately is not 100% clear at this point either. - I believe I understand what your looking to do, and I hope you are successful if you try it.

 

[B23]

With the introduction of the 230 SMK and the planned introduction of a 245 Berger, I was considering a new 30 cal build. Rather than going to something requiring a 0.590" bolt face I thought I'd take advantage of all of my on-hand 300 Win supplies and try a reamer with longer freebore than the SAAMI spec reamer I have been using. I'd probably use a long 9-twist barrel...maybe 30".

Any speculation on velocity with the 230s? Does anyone feel this will be a lesson in futility?

Nothing wrong with the tried and true 300 Winnie but if you are wanting to sling those 230's or the new 245 and still stay on a mag bolt face, I think you would benefit from stepping up to a 300 RUM or 30 Nosler. If you plan to stick with the 300 Win I'd crunch the numbers because you may find out you can't get those 230's+ going fast enough to out perform the lighter 200gr SMK or 215 Berger. That new 200gr SMK should make for a very sweet long range bullet for ringing steel out of the 300 Win and the BC of that new 200gr SMK is the same as the 230 Berger. Don't know that the design of those new SMK's will make for a very good hunting bullet because I'd be concerned they'd act like a FMJ but they should be good for ringing steel.

I talked to Sierra yesterday about their new 200 & 230 SMK because I'm wanting to give them a go out of my 30-338 Lap Imp, the Sierra Tech told me at the speeds I'll be launching the 200's at my 1-10tw should be fine but I'll need a 1-8tw for their new 230's so if you plan on shooting the 230 SMK you may want to order a 8tw barrel instead of a 9tw.

And for what it's worth, these new SMK's are wicked looking bullets. I got some of the 200gr SMK's yesterday and I'll have some of the 230's tomorrow. Those 200's have a very short bearing surface, it's only .335, and they look like a missile ready to launch just sitting there.

 

[Zero333]

I get 2,744 fps in a 26" bbl with RL-33 and the 240 SMK. in a 300winmag.

The chamber has so little freebore that half (or more) of the 240 smk is below the case mouth.

The loads I made up ran up to 2,800 fps with out pressure signs and I didn't care to go higher since the accuracy at 2,744 was excellent.

Remember this 2,800 fps is from a very short freebore 26" bbl with 240 smk and RL-33.
F.C. (from FGMM) brass and 215m sparkplugs. COAL was 3.450"ish.

I'll speculate that with the right amount of freebore, a 30" tube, RL-33 and the 230 SMK should get 2,900 fps. in a 300winmag

 

[FatBoy]

I'm running a 26" barrel with an A191 chamber, 1:10 twist in my 300WM. With a 230gr OTM I easily run 2780fps with Retumbo, with room to go up. Like Zero333 about half of the bullet is in the case, allowing .030" jump. I can push these OTMs out another .035" or so and still mag feed but I'd be right on the lands or in, and I'm not comfortable with that. Six firings on the Winchester brass at this point. I think 4" more barrel I would see 2830-2850, maybe faster with H1000 or N570, etc.

My next 300WM barrel will be an 8.5 or 9 twist.

 

[Bart B.]

I think belted cases are loosing popularity as a super accurate cartrige to reload. A second body collet die is often needed to size the case body all the way back to the belt after full length sizing.

www.larrywillis.com.

Get one and use 300 Win Mag cases and they'll do fine. One if the big rimless cases is probably a better choice.

 

[Wingnut00]

For what it's worth, 230 Berger loaded at 3.775 oal in a mark 248 mod 1 chamber it's pretty easy to get 2900 with h-1000 out of 26" stick.

 

[Jason Boersma]

With a 30” barrel and H1000 I can push a 215gr hybrid to over 3000fps with my 300WM. You just need to get the bullet at least to 2850fps, most cartridges over 6mm shoot good at that velocity

 

[MagnumManiac]

My chambers are also A191 with a 1:10” twist.
I get above 2950fps with the 215gr Hybrid in a 28.5” barrel, just docked it from 30” with a re-chamber.
I tried the 230gr Berger a while back, wasn’t impressed with it, so still need to find a powder that it likes.

Belted cases do NOT pose a problem if the correct sizing techniques and the correct chamber is used. I have Lapua 300WM brass from the 80’s that has never swelled just above the web, many firings later and it still has tight pockets.

That Larry Wilis die MAY be required for Norma cases in an oversized chamber, but generally speaking it should never be necessary.

Cheers.

 

[cmillard]

i would go with a .300 rum or a .300 wsm with a 9 twist in either one of those chamberings. the belt is just one more thing to mess with even though you can headspace in other places, it is just in the way. I had a custom .300 WM and wasn't a fan and switched to the WSM and loved that short fat round

 

[buckbrush]

I’m not discouraged by the belt. I’ve never had issues with it in many years of loading 300 Win Mags.

I should have been more clear in my original post and asked if the 300 Win could push the 230 bullets fast enough to wring the extra BC out of them.

Thanks for the input so far!

 

[Alex Wheeler]

If you really want to run 230s fast on a standard action this may be worth a read
http://forum.accurateshooter.com/threads/30-28-nosler.3927522/

 

[007]

I have begun building a 300 Win Mag with similar goals.
30” Rock Creek 1:8.5 twist
Chamber is for Berger 215/230/210.
Also going to try the Flatline 198 gr copper solid.
H1000 pushes the 215 around 3000 FPS....RL26 almost 3100 FPS.
Flatline’s will be supersonic past 2000 yds.
The 215/ 230 Berger and the Warner Tool bullets have breathed new life into the 300 WinMag if you have a rifle that can shoot them.

 

[cmillard]

Back when I still had my win mag, I used retumbo primarily. Good heavy bullet powder