I have some 175gr Sierra Matchking (MK) bullets. These are not the new tipped variety. I want to shoot them in a 300 H&H rifle with a Parker-Hale M82 barrel. It has a twist of 1:12". Rotational stability is not an issue. That is the twist used for decades in military 7.62 NATO (.308) and 300 Win Mag sniper rifles built to shoot Sierra's 175gr SMK bullet. I have looked and looked but I cannot find any load data for that bullet in the 300 H&H. I've looked through every reference I have and I've diligently searched online. I even asked Sierra (black hole).

Does anyone have some loading data, perhaps from a 1970s to 1990s load book? I'm not interested in computer-generated or hypothetical data. I can create that myself. I might end up having to go that route but I'd prefer a good starting load or two from a reputable source.

Thanks.

Contact me via pm with your phone number. I will text you photos from an old Sierra manual.

drm-hp sent some info from Sierra's 3rd Edition. The old sheets don't have specific info for the 175gr SMK. But they do list info for the 168gr SMK and the 180gr SMK. I'll just use a happy medium for the 175gr.

For example:

168gr SMK and IMR-4350
Start load = 60.5 grains for 2700 fps
Accuracy load = 66.9 grains for 3000 fps
Maximum Load = 69.1 grains for 3100 fps

180gr SMK and IMR-4350
Start load = 55.4 grains for 2600 fps
Accuracy load = 62.8 grains for 2800 fps
Maximum Load = 65.1 grains for 2900 fps

That tells me for the 175gr SMK I should work up an accuracy load of IMR-4350 to around 2900 fps. Using Sierra's data that would take about 65 grains of IMR-4350. But rifles differ so I'll start with less and carefully work up to whatever gives me 2900 fps., whether it's more or less than 65 grains and as long and it's safe to get there.

Thank you drm-hp!

I think Ray Atkinson has posted previously how he got a .300 H&H shooting at similar velocity to a .300 Win Mag. Don't know with which projectiles but a quick PM might elicit a bit of data for you.... maybe.

Thank you for that. However, it is not at all difficult to work up 300 H&H loads to 300 Win Mag velocities. Some factory loads available also match or are within a hair of 300 Win Mag velocities. For example, Nosler offers 300 H&H in a 180gr Partition loaded to 2950 fps and a 180gr Accubond loaded to 2950 fps, both loads producing 3478 ft-lbs muzzle energy.

My goal here is to find an accurate load for the 175gr Matchking bullet. It's not a good bullet for hunting. But with a muzzle velocity of 2900 fps (not a max load), it should be very accurate and remain supersonic to 1200 yards. That's much farther than the 600 yards I plan to shoot it.

quote:

Grenadier
posted 20 June 2021 11:13
Thank you for that. However, it is not at all difficult to work up 300 H&H loads to 300 Win Mag velocities. Some factory loads available also match or are within a hair of 300 Win Mag velocities. For example, Nosler offers 300 H&H in a 180gr Partition loaded to 2950 fps and a 180gr Accubond loaded to 2950 fps, both loads producing 3478 ft-lbs muzzle energy.

My goal here is to find an accurate load for the 175gr Matchking bullet. It's not a good bullet for hunting. But with a muzzle velocity of 2900 fps (not a max load), it should be very accurate and remain supersonic to 1200 yards. That's much farther than the 600 yards I plan to shoot it.

Fair enough. Point taken, thankyou.

You didn't mention which powders you are interested in. I use IMR7828SSC in my .300 H&H under a 180 Nosler Accubond. 73.5 grains yields a velocity of 2960 fps from my Sako's 24.4" barrel. This has been a great powder in this rifle, which exhibits very low velocity spreads and consistent 3/4 MOA groups.

If you wanted to try it with the 175 MK's for target work I'd recommend starting at about 72 grains and adjusting based on results.

I've used several different powders all with excellent accuracy results. Brass is WW and RP, the RP yields about 40 fps faster velocities; primers are CCI (their magnum) and Fed 215.
Starting loads are:
66gr IMR 4831
68gr Re 22
70gr IMR 7977

These were low 2,900 fps in a stock winchester 26" bbl