338 300 grain SMK test results

[goodgrouper]

i'd like to hear the formula to safely shoot these bullets at 2000 instead of 3000. where i shoot 500 and over i can't drive or ride anything. i have to carry everything i need about 600 yards and then carry everything out to the target area, whatever distance it might be.i don't mind some exercise but it is extremely time consuming and that's what i'm short on. you mentioned a powder you were using to shoot at much slower speeds but is there a filler or something else involved to do this?

I did not use any filler. It was just 60 grains of N170 which was the slowest burning powder I had on hand. There was lots of air space in the case but it didn't matter.

 

[goodgrouper]

GG,

On your findings, if I am not mistaken the 250's are made from the same jacket cups as the 300's thus a thicker jacket. Also if I remember right when I cut a 250 apart when they first came out several years ago the lead core goes clear to the tip. The 300 of course has an air gap from the tip to the core allowing the tiny SMK hollow point to actually work. I haven't had any apart for quite sometime but that is what I remember.

Thanks for reporting your findings. That would make perfect sense.

 

[Chawlston]

GG,

What muzzle velocity are you getting with the 225s to get 2179fps at 1000 yards? I am getting 3220fps out of my rig w/225s and the JBM program lists the 1000 yard velocity as 1683.5fps. If you are getting 2179 at 1000 yards, that would probably set my chronograph on fire at 21 feet.

James

 

[jwp475]

Your speed of 1683 fps at 1K is based on an elevation of about sea level get up to the 8 to 10,000 feet of elevation where gg hunts and your velocity will around 2106 at 10,000 feet of elevation

 

[davewilson]

i called the sierra tech line today to see if they could clarify some of the things we've been kicking around in close but no cigar type of detail. they use the same exact cup to make each bullet as Shawn said. of course the 250 has to be trimmed a little because it's shorter.this does make for an ever so slightly thicker jacket on the 250. the base of the bullet is .050 thick and tappers to .012 at the tip. everything is the same on the 300 except the jacket is .011 thick at the tip. they both have the same exact hollow point behind the tip except the 250 would be ever so slightly smaller because of the .001 thicker jacket.anyways, this is what the tech said his spec sheet had on the 2 bullets.

 

[goodgrouper]

GG,

What muzzle velocity are you getting with the 225s to get 2179fps at 1000 yards? I am getting 3220fps out of my rig w/225s and the JBM program lists the 1000 yard velocity as 1683.5fps. If you are getting 2179 at 1000 yards, that would probably set my chronograph on fire at 21 feet.

James

I am getting 3325 fps and I checked my bc at .568 and I run my charts anywhere from 4500 to 10,0000 feet elevations.



Dave,
thanks for reporting your Sierra inquiry. Good to know.

 

[Chawlston]

GG.

My data is at sea level and I guess that is the difference. I was hoping you had some majic potion for me to use on my loads to squeeze a little more perfomance out of my 338RUM. With 101gr of H1000 and a 5.5 foot drop tube, I basically ran out of case capacity. No pressure signs at all. Thanks again.

Chawlston

 

[goodgrouper]

As promised, here are the photos of the test bullets.

Here is the accubond:

And here is the 300 SMK's. The darker one is the one out of a cow moose's shoulder at 982 yards:

 

[1doug]

deleted

doug

 

[oltmann]

Nice test, and good results.

Just for giggles, do you mind getting the weight of the SMK you recovered from the moose?

 

[goodgrouper]

Nice test, and good results.

Just for giggles, do you mind getting the weight of the SMK you recovered from the moose?

I could weigh it but there is so much tissue and fat on it that it wouldn't be an accurate number.

 

[royinidaho]

I could weigh it but there is so much tissue and fat on it that it wouldn't be an accurate number.

Find and ant hill, after you boil it.

 

[Lapua Hunter]

I have used 300 SMK on Oryx at 700 yards and mule deer at 162 yards, both with decisive results.

 

[crittergitter]

I sure would like to have someone explain to me how the 250 grain SMK can be a FMJ and the 300 be so much more explosive. I just don't get that. The sectional density of the 300 is way higher and both bullets are made of the same jackets and I presume the same lead.

I'm new to the big 338 arena, but I have smacked 3 whitetails with the 300 smk from the new long gun this season. 2 were just under 200 yards and one was at 475 yards. I'm pushing the 300 SMK at 2965 fps from a 34 inch barrel with 105 grains of US 869 in a 338/300 RUM. All had .338" entry holes with near explosive results after a few inches of penetration. I figure that the 300 SMK opens quicker than the 250 SMK because the non-bonded 300 SMK core itself has a higher SD than the core of the 250. I would guess that at impact the less dense jacket of the bullet would slow down faster than the core, causing the core to slam into the nose of the bullet and pry open that tiny hollow point. The more lead and jump space in the shank of the bullet, the more the nose of the bullet will open on impact, and the greater potential for the hollow point to build hydrostatic pressure...or just grab stuff and fragment. If the 250 SMK does not have enough SD, it may not dislodge the core as violently as the 300 SMK. The bowling ball thing surprises me though. Maybe the hollow nose of the 300 crumpled on the surface of the ball but the point of the 250 penetrated.?

Thanks for the helpful test results. I can't stay on target with the 300's either but they are so accurate that I don't want to experiment right now.