Home Forums Reloading Big Game Rifles Sierra 375 300 gr btsp?

Anybody got an idea of the bc on this bullet? Magnum Man

Midway shows the 375 300gr game king at .475

yup

Thanks guys MM

And it is a TOUGH bullet btw!

I loaded some of these in WW brass with CCI-250's and IMR 4320 they shot in decent groups. The 375 in question is a Ruger 77 Express. Fotis I note that Boddigton likes them for African antelope because they are soft and expand well. MM

All I can say is this MM........


I was thinking about using this bullet in my 378 Bee. I do not really trust them with the jacket core separation in the past so I played with it.

Out of curiosity I shot one 300 gr Sierra gameking in wet newsprint out of my 378 Bee at 3050 fps MV. Impact was at 40 yards. Opened up to 70 plus caliber and retained 214.5 grains. Now if all of them do this I am IMPRESSED! Will found out tomorrow what they shoot like.

MM,

Two decades back, Federal loaded the 375 Sierra BTSP in their Premium ammo and I bought several boxes on a close-out deal.

I used the bullet on caribou and a moose or two with OK results until I shot a fork moose at 20 yards and only made him jump. This bull was in a mowed field....no twigs or brush and standing broadside....WTH?......my second shot dumped the bull and while butchering, I was finding scattered bullet parts just under the hide.

I can only surmise that the bullet fragmented prior to impacting the moose.

I went back to my bear load of TBBCs

They did change it over the years I thought. Tougher now. I amy be wrong though.

I don't think Sierra has changed the bullets they sell as components much if at all over the years. What they sell under contract with other companies might be another story. Rather than using any kinds of jacket rings or bonding to control expansion characteristics however, they rely soley, it seems, on jacket thickness and hardness/toughness together with core alloy and hardness to control expansion. I know both the 300 Gameking in .375 and the 250 Gameking in .338 (and 225 .358) have hard cores which make the bullets quite tough. They are however, malleable enough to act somewhat putty-like while in action. I have recovered or seen several that worked like that anyway.



This is one of two 250 .338s I've seen used on moose. This bullet appeared to be a well-expanded, intact slug when I pulled it out of the DRT bull (moose) it killed (at just over 200 yards). It was when I was washing it off that it came apart and I realized that the core had actually been 'feeding out' of the jacket as it expanded. I found the jacket of another of the same in the snow beyond another bull which I killed at around 400 yards. The core went on deeper into the drift where I couldn't find it. I hit that animal about 6 inches apart with two different 250 grainers - a Gameking and an Interlock while he stood in one spot. Both bullets penetrated the meaty area of the legs below the shoulders. The Interlock made it into the far side. The Gameking went all the way through.

I have had or seen similar results with the 300 .375. I generally prefer Interlocks simply because I have had better luck getting them to shoot well consistently in my hunting rifles. But there are a lot of ways to improve on either of them for hunting - which isn't to say that they can't get 'er done.

Another picture of the 300 sierra at 3000 fps impact

Wet newsprint is a basic 'soft tissue' test for most bullets. The bullet I pictured is an actual soft tissue test as no bones were broken in that moose. My bullet was started at 2850 - 2900 fps, so how fast it was going (at sea level) by the time it hit the animal is up for interpretation.

I presently load the 250 Partition Gold in that rifle- though isn't hasn't gotten 'air' for a few years.

I will be using the 250 TTSX 260 Accubond or 265 HV GS Custom based on accuracy results.

Thanks for all the add'n info. Magnum man