I use 110-130 gr. for 300 to 600 yards and was using 168 gr. SMKs for pds over 600 yds. I had a bunch of them and have finally used them up. In the future I would like to try some Wildcats, but my first trip of the summer is coming up in 3 weeks and I am going past some shops this weekend. Sooo...
The rifle is a 300 WM with a 30" heavy barrel. I have IMR 4831, 4064, IMR 4350, AA 4350 (slower), XMR 4350 (as slow as burning wood). I also know how to buy powder I don't have. I guess what prompts this question is the trade off between recoil and performance/BC. Not that recoil bothers with this rifle, but I want to try to get back on the target to see the impact so I don't need a spotter.
1. So for pds 600 to 1000 yds, what SMK (over 168) would you recommend in a 300WM?
For the 190SMK, id try 67.5gr of IMR-4350. its about the lowest recoil full velocity loading youre going to get. 2920fps is what my chrony says from a 26" barrel, so yours will be faster.
My personal preferance is towards the heavier bullets, speciffically the 220s. This bullet gets launched with 73gr of H1000 at 2692fps.
Neither of these loads are near max.
I don't have a lot of experence with the 200SMK, so ill leave that one for somebody who does.
Now as to the issue of being able to spot your hits, im not sure either of these loads will get you there. Ive spotted hits with both of these loads from a 13.7lb rifle, but never closer than 1100yds. Im convinced that about the only way to spot hits with a rifle producing this much recoil is to use a bench style stock with a flat buttstock. if youre already setup that way, the 220 is the way to go. IMHO
I think if I were in your position, id have a look at the recoil that a top load for the 175SMK develops compared to the heavier bullets. They will give up a good bit as far as wind deflection is concerned when compared to the 190s and 220s, but are MUCH better than the 168s you were shooting.
Wow. I just did some research that I likely should have done earlier. I knew the 168s were at .462 and the 190s were .533. I didn't even research the 175s as they were so close (in weight) to the 168s I reasoned I wouldn't be gaining anything. At .505 they are way closer to the 190s than the 168s. Is that correct???? The 180s are .475????
As for recoil, my rifle is over 20 lbs. and I can get it "back on" to see hits with the 168s using bags. With a rest that captures the butt pad I think I can go heavier.
yep, that 175SMK is quite a bullet.
The folks at the drawing board had their hats on straight the day they designed it for sure.
The 175SMK is one of the few bullets ive had the chance to test for BC across the Chronys... we measured them at .529 (corrected for standard). 190s went .561. Sierra's published figures are lower for both bullets, and the 220SMK as well for that matter, but in my testing, they gave up very little to the Bergers of the same weight (175s).
You could also try one of the VLD style bullets like the 155gr Berger and the 155gr Lapua both of those have a BC above .500 and you could launch them alot faster than the 175 or 190's. Also the 155gr Sierra Match King Palma bullet has a realy high BC for its weight as they are made to shoot out to 1k with a 308 so with you 300mag you could realy get some range out of it.
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You could also try one of the VLD style bullets like the 155gr Berger and the 155gr Lapua both of those have a BC above .500 and you could launch them alot faster than the 175 or 190's.
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The published bc on these three 155gr bullets are:
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Also the 155gr Sierra Match King Palma bullet has a realy high BC for its weight as they are made to shoot out to 1k with a 308 so with you 300mag you could realy get some range out of it.
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True the 155 was designed primarily for the 308Win out of longer barrels for 1k (2950fps or faster is tough in a 24" barrel) but it won't even come close to the downrange capabilities of the 175 or 190SMKs. Trajectory will be flatter for some closer ranges, but if you limit comparisons to any single case, in a given barrel length, the heavier bullets win every other category hands down.
downrange velocity, downrange energy, and wind deflection of the heavier bullets are all superior to the lighter bullets, especially the 155SMK.
At any ranges past 600-800 yds, the high BC (due to wind deflection) is so much more important than flat trajectory that there is no comparison.