Sierra 69 grain SMK shoots great-TMK, not so much.....

I have found that 24.6 grains of H4895 and a 69 gr SMK shoots around .3 MOA at 300 yards and I'm very happy with that.

I picked up a box of 69 grain TMK and tried the exact same recipe and needless to say, I was NOT that happy.

Curious what was required of those who made the transition from the SMK to the TMK. What were the changes from your established load that were required to get the TMK to shoot...

Yeah, I know-why change what works..... I've been shooting 300 yards and will be shooting 600 yards fairly soon and want to be prepared.

I found the TMKs preferred to be closer to the lands. In my particular rifles, a .22-250 and .243 they like to be just kissing the lands and they shoot just as well as the normal ones.

I shot the TMK over Varget yesterday in my 8 twist CBI .223 barrel. Shoots very flat compared to the SMK. Hornaday ballistics program says I should be at about 2000 fps @ 1000 yds when launched at 3140. Groups are generally 1/3 minute. MY pet 69 SMK load was over 8208. Shot reliably at 750 yds. Hope to get out to the 1000 yd range soon and get some trigger time with the 69TMK. Should be interesting!

Thanks for the info guys.

Stomp, did you change anything other than the jump with your loads?
T10, is your current Varget loading giving you 3140 or are you working up to it still?

On the .22-250 no. No other change other than seating depth. The .243 was a start from scratch deal so had no previous load to try first. I just found that during load development the less jump I had the better they shot.

I did a LOT of testing with the 69gr TMKs in my .223 including several types of powder, different charge weights, and seating depths. I never got them to shoot as well as the 69gr SMKs. The SMKs, which I moly coat using the wet method, are my go-to bullet for my .223 with a 1:8 twist barrel. In side-by-side testing with the TMKs, the SMKs win but I don't know exactly why.

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Originally Posted by copterdrvr

Thanks for the info guys.

Stomp, did you change anything other than the jump with your loads?
T10, is your current Varget loading giving you 3140 or are you working up to it still?

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I'm using 25.9 gr Varget, CCI400 and Win brass and the TMK clocks in at 3120-3140 fps sitting .005 off the lands, and using another shooters new Chrono.

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Originally Posted by stomp442

I found the TMKs preferred to be closer to the lands. In my particular rifles, a .22-250 and .243 they like to be just kissing the lands and they shoot just as well as the normal ones.

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Stomp, what twist is your 22-250? Mine is a 12 twist and the Berger stability calculator says I would have better luck catching fish in the desert than try 69 grainers.

Thanks for the info guys!

T10, how do the primers look and any bolt lift problems? I'm shooting a Savage FLV and my load leaves a very TINY bit of primer flow around the firing pin strike mark but the shoulders are round and no bolt lift problems. I'm figuring its just a slightly oversize firing pin hole in the bolt face.

I'm going to the range to chrono tomorrow, but it looks like my load of 24.6 of H4895 should be around 2910 as it is right now and I'm curious if your load shows any pressure signs.

Mine is a 12 twist as well, but our local range sits at exactly 3000 feet above sea level and my shooting only goes higher from there. They stabilize just fine for me in two different barrels now and hold half MOA or better out to 700 meters.

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Originally Posted by copterdrvr

Thanks for the info guys!

T10, how do the primers look and any bolt lift problems? I'm shooting a Savage FLV and my load leaves a very TINY bit of primer flow around the firing pin strike mark but the shoulders are round and no bolt lift problems. I'm figuring its just a slightly oversize firing pin hole in the bolt face.

I'm going to the range to chrono tomorrow, but it looks like my load of 24.6 of H4895 should be around 2910 as it is right now and I'm curious if your load shows any pressure signs.

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No primer issues beyond what you describe. Less apparent when using BR-4 primers, as they have thicker cups. No bolt stickiness either. It is a warm load, but not in excess of published loads, not that that is a definitive line in the sand. Ya gotta be careful, right?

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Originally Posted by stomp442

Mine is a 12 twist as well, but our local range sits at exactly 3000 feet above sea level and my shooting only goes higher from there. They stabilize just fine for me in two different barrels now and hold half MOA or better out to 700 meters.

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Just curious, if you plug your data into the Berger stability calculator, what SG do you come up with at your altitude and temperature?

The calculater claims unstable with an SG of .939 in 95 degrees and 3000 ft elevation and that my BC is being compromised by 17℅ but they shoot nice little groups and definitely buck the wind better than the standard match King for me and they are very hard on coyotes.

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Originally Posted by stomp442

The calculater claims unstable with an SG of .939 in 95 degrees and 3000 ft elevation and that my BC is being compromised by 17℅ but they shoot nice little groups and definitely buck the wind better than the standard match King for me and they are very hard on coyotes.

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I calculate you are getting about 3600 fps, is that pretty close?

Care to share your recipe?

My Chrony claims 3440fps. I am running 37gr of Reloader 17 in Winchester cases and CCI primers.

Yep, BR-4's are my primer of choice too.

Went to the range today and found I was alittle shy on the velocity guess as it averaged out to 2995 fps. Going to try the same load and the TMK's with less jump and see what happens.

Fling-winger, what it the twist rate on the barrel you're shooting? If it's 8 or faster, give the 77 TMK a try. I shot them yesterday for the first time. Some good groups at 200 yds that'll need refinement, but looks promising. And the Berger twist rate calculator says stable.