6.5 SST

reubenski

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I just started load development and figured I would start a thread on it. I have two barrels. A steel McGowen 6.5mm 1:8" 26" Heavy Palma and a Carbon Six ( CF wrapped McGowen blank) 1:8" 26" Magnum contour. Both on a Tikka T3 action.

I plan on shooting the Berger 156 EOLs in the CF barrel for hunting and the 147s in the steel barrel for matches and load development. I plan on doing all the load D in the steel barrel and exporting it to the CF barrel. Both chambers are cut with the 6.5 SST II reamer. So far I've figured the 147's are at 2.930" COAL to the lands with this reamer. The Berger 156's are at 2.992" with this reamer.

I'll be trying H1000, RL26, H4831SC, and IMR 8133.
 

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Lunchbox27

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I'll be following this closely. I've been wanting to see this cartridge out in the wild, but haven't yet. The idea of launching a 147 @ 3000fps tickles me.
 

charnicus

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Tagging in. Waiting on my barrel from PVA at the moment. That COAL scares me as Rich said I would be nowhere near that long with the SST 2 reamer and 150 class bullets.

Have you explored any die options other than those offered from the site?
 

reubenski

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Ya, I was surprised to see these COALs. That pretty much makes 156's and 150's unusable out of a repeater unless I find a long jump that they like. 147's it is I guess....
 

reubenski

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McGowen button rifled, 1:8", 26", Heavy Palma. 11rds fired and then cleaned.

H1000, 147 ELDM, 2.910", FM215
54gr 2793fps SD 2.4
55gr 2847fps SD 1
55.5gr 2864 SD 4
56gr 2888 SD 3 *good accy

IMR 7797, 147 ELDM, 2.910", FM215
54.5gr 2763 SD 3
 

charnicus

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Ya, I was surprised to see these COALs. That pretty much makes 156's and 150's unusable out of a repeater unless I find a long jump that they like. 147's it is I guess....
I was talking to Jeremy over at PVA about this and he had mentioned 153 Atips as a candidate but they’re size specs are not published.

Not that it’s necessary to be on the lands it’s nice to have that possibility and be inside mag length (short action for me). Worried that the SST 2 reamer isn’t going to be a good option.
 

reubenski

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I think the SST II reamer is too long. It's perfect for the 147s. I'm really puzzled by it bc the numbers I'm seeing are not what Rich was putting out.
 

charnicus

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I think the SST II reamer is too long. It's perfect for the 147s. I'm really puzzled by it bc the numbers I'm seeing are not what Rich was putting out.
Like nearing a tenth of an inch longer...
 

reubenski

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McGowen button rifled, 1:8", 26", Heavy Palma. 23rds fired in the barrel

RL26, 147 ELDM, 2.910", FM215
54.5gr 2911fps SD 11
55gr 2937fps SD 7
55.5gr 2968 SD 9 *starting to show pressure signs
56gr 2989 SD 5 *stiff bolt lift on 2rds

Good Accy ~ 3/8's"
 

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reubenski

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McGowen button rifled, 1:8", 26", Heavy Palma. 41rds fired in the barrel, cleaned.

H1000, 147 ELDM, 2.910" COAL, FM215
56gr 2883fps SD 9
56.5gr 2920fps SD 11
57gr 2935fps SD 14
57.5gr 2972fps SD 10
58gr 2992fps SD 4

IMR 7977, 147 ELDM,2.910" COAL, FM215
57gr 2887 SD 1
57.5gr 2906 SD 2
58gr 2938 SD 6 * pressure
 
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charnicus

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McGowen button rifled, 1:8", 26", Heavy Palma. 41rds fired in the barrel, cleaned.

H1000, 147 ELDM, 2.910" COAL, FM215
56gr 2883fps SD 9
56.5gr 2920fps SD 11
57gr 2935fps SD 14
57.5gr 2972fps SD 10
58gr 2992fps SD 4

IMR 7977, 147 ELDM,2.910" COAL, FM215
57gr 2887 SD 1
57.5gr 2906 SD 2
58gr 2938 SD 6 * pressure
I like those numbers with the H1000 assuming you weren’t close to pressure at 58gr. Speed is nice too.
 

reubenski

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I like those numbers with the H1000 assuming you weren’t close to pressure at 58gr. Speed is nice too.
I'm probably getting close. It appears this barrel is slow. I'm very surprised that I pressured out with RL26 before getting to 3000fps. I'm going to try Retumbo, RL33, and 8133
 

charnicus

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I'm probably getting close. It appears this barrel is slow. I'm very surprised that I pressured out with RL26 before getting to 3000fps. I'm going to try Retumbo, RL33, and 8133
What about running 210m primers since the grains aren’t quite at 60?
 

charnicus

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I'll give it a shot
I came across this last night. Might be some additional data.

 

reubenski

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McGowen button rifled, 1:8", 26", Heavy Palma. 65rds fired in the barrel, cleaned.

H1000, 147 ELDM, 2.910" COAL, FM215 virgin brass
58gr 3004fps SD 5
58.5gr 3034fps SD 7 *warm
58.5gr 3043fps SD 14 (1x fired brass) * hard bolt lift
58.5gr 3050 SD 10 (FM210 primer, virgin brass) no pressure

H1000, 156 EOL, 2.930(60 thou jump), FM215

56gr 2905 SD 6
56.5 2935fps SD 14
56.5 2928fps SD 9 (2.970" coal, 20 thou jump) light pressure signs.
57 2965fps SD 5 * hard bolt lift

Accy on the Bergers was so-so ~ .5

Accy on the 147s was good ~ .3 to one hole at times
 

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charnicus

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The 147s look pretty winning. That one holer though. 👌🏻
 

charnicus

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Went out today and did a seating depth test on the 147's with 58gr H1000. 10 thou jump did best although 20 and 30 thou didn't suck either. Looks like a 147 @ 3000fps is a good load.
That’s awesome man.
 
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charnicus

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Fuck. Where’s the tail of the bullet end up at that length?
 

reubenski

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IMR 8133, 147 ELDM, 2.920(10 thou jump), FM210

59gr 2905fps
59.5 2935fps
60 2955fps
60.5 2973fps slightly compressed
61 2985 compressed

Pressure was difficult to tell. I loaded 5 of each charge weight. Since my MPA/ Magneto bayonet adapter doesn't mount with the correct height on a KRG spigot I shot two rounds from each 5rd ladder over the Chrono. I got slight bolt lift at 59.5grs, bolt lift and faint ejector marks at 60, and hard lift and full ejector marks at 60.5. so I didn't bother shooting 61. Then I shot 3rd groups at 300. Funny thing is I got zero pressure when progressing up the ladder so I shot 3rds of 61grs for a group and the remaining 2rds over the Chrono. No pressure. So a little baffled as to what to think. But regardless the accuracy wasn't really what I wanted. So I'm probably not going to investigate.c Accuracy at 300yds was .6/ .7 moa.
 
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reubenski

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Doing some load confirmation in prep for 1st season antelope in two weeks. I only had 5rds of the old lot of H1000 left that I had loaded. 58grs under a 147. That previously gave me 3000fps. Today, with 150rds on the steel barrel, it was going 3090 with no pressure. Interesting. The barrel sped up and in a hurry. I loaded up a ladder with the new jug of H1000 that I scored. The 147's are also from a new lot now. A bulk 2000ct lot from Midsouth. These are the results.

McGowen button rifled, 1:8", 26", Heavy Palma. 150rds fired in the barrel. Cleaned 50rds ago

H1000, 147 ELDM, 2.920" COAL, FM215 virgin brass

56gr 3000fps SD 8
57gr 3037fps SD 2.8
58gr 3084fps SD 2.6

*All good accuracy



Carbon Six, 1:8", 26", Magnum contour. 25rds fired in the barrel. Not yet cleaned

H1000, 147 ELDM, 2.920" COAL, FM215 virgin brass

56gr 2922fps SD 7
57gr 2962fps SD 4

Seems like if this CF barrel speeds up in a similar manner as the steel barrel it will shoot the same load/ speed. H1000 and 147's also seem to give good accuracy but I haven't shot this barrel at 300yds yet to see.

No pressure in any of the above loads/ barrels. As a bonus I was able to confirm another data point of the two barrels returning to zero after swaps. The CF barrel is 1.4 mrad low and 1 mrad right from the steel barrels zero. Repeatable.
 
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reubenski

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Also knocked out a quick and dirty Satterlee single round ladder with RL23 and H4831SC. Surprised at the results.

RL23, 147ELDM 2.920" COAL, FGM 215, virgin brass on the steel barrel.

52gr - 2949
52.5 - 2958
53 - 2970
53.5 - 3001
54 - 3022
54.5 - 3047 faint ejector mark
55 - 3070 no pressure signs
55.5 - 3097 ejector mark

*No stiff bolt noticed




H4831SC, 147ELDM 2.920" COAL, FGM 215, virgin brass on the steel barrel.

53gr - 2934
53.5 - 2966
54 - 2978
54.5 - 3006
55 - 3031 ejector mark
55.5 - 3048 no pressure signs
56 - 3071 ejector mark
56.5 - 3096 ejector mark

*No stiff bolt noticed with H4831SC either
 

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reubenski

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I've been continuing to put rounds on the Carbon Six barrel to try to get through the speed up process. I shot 57.5gr of H1000 at 3040fps earlier this week and it showed better accuracy potential at 300yds than 56grs did. I went out a second time with 57gr loaded up and shot 300yd groups with .015" jump and .030" jump. Like my previous tests the 147's seem to like less jump. Going out this morning foul the bore after cleaning, check speed on 57gr because I think the barrel is already speeding up, and true the 147's at 1100. We'll see what happens.
 

Milo 2.5

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McGowen button rifled, 1:8", 26", Heavy Palma. 23rds fired in the barrel

RL26, 147 ELDM, 2.910", FM215
54.5gr 2911fps SD 11
55gr 2937fps SD 7
55.5gr 2968 SD 9 *starting to show pressure signs
56gr 2989 SD 5 *stiff bolt lift on 2rds

Good Accy ~ 3/8's"
How much room is left in the magazine with your seat depth?
I have been following this post, looks interesting, thinking of trying 25 SST with BJ ace bullet. I have almost hit buy on brass and dies, not sure if proprietary stuff suits me.
 

reubenski

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How much room is left in the magazine with your seat depth?
I have been following this post, looks interesting, thinking of trying 25 SST with BJ ace bullet. I have almost hit buy on brass and dies, not sure if proprietary stuff suits me.
50 thou in an ARC mag, 60 thou in a binder less AICS mag. This is using a 10 thou jump with a 147 on the SST II chamber. If you want to shoot 150's or 156's you'll need the original, shorter throated SST Gen I reamer.
 
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reubenski

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Just finished fouling the bore, checking speed and truing the 147's at 1100 and 1200.

57grs now gets me 3030fps SD's under 10. I zeroed at 300 and set the elevation turret to + .8mrad to ballistically maintain a 100yd zero. Leaving the scope on .8 I held over 7.1 mrad and connected on the 3rd shot with 1.9mrads of wind on the 18" 1200yd target. The next two rds need anywhere from 1.3 to 1.6 L->R wind. This means I had a 11mph effective wind on top of my .3 mrads of spindrift. If you believe in Aerodynamic Jump the 11mph L->R wind required another .1 of elevation. So a .340G7 worked. If you don't believe in AJ the BC would work out to .330.

So then I transitioned to the 1087yd target. It was a well shot up 100% IPSC so telling where I was hitting was a challenge. The 5700AB was calling for 6.7 so with .8 still dialed I connected with 5.9 a little low. I dialed 6.7, hit on the low side, dialed it up to 6.8 and hit a bit more center. Using around a 1.4mil L->R wind hold. Again, this lines up with a .340G7 if you factor AJ. I wanted to shoot some smaller, shorter range stuff where I'd actually be shooting antelope at but I was out of ammo.

Good news is that I had no blow ups with the 147's, no pressure, sub 1/2 moa groups at 300, and the BC was generally on and not dissapointingly low.
 

reubenski

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Nailed an antelope at 596yds Saturday morning. The 147 ELDM performed really well with a body shot. The wind was blowing a little harder than I thought so I hit a little farther down the body than right behind the shoulder. It was a little anticlimactic. All the prep work, barrel ordering, waiting on them and the reamer, getting the rifle together, load development, tracking the scope, truing the BC, etc .. and it was done an hour after legal shooting light. Really want to hunt with the rifle some more.
 

charnicus

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How much room is left in the magazine with your seat depth?
I have been following this post, looks interesting, thinking of trying 25 SST with BJ ace bullet. I have almost hit buy on brass and dies, not sure if proprietary stuff suits me.
I ended up in the same boat just one step further and had PVA do a barrel for it. It’s no secret about people’s experience with them and I fit right in that mix. Despite how exciting @reubenski has made the round sound I find it hard to keep charging forward with another wildcat that in my humble opinion might be the best sa magnum.
 

Milo 2.5

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I ended up in the same boat just one step further and had PVA do a barrel for it. It’s no secret about people’s experience with them and I fit right in that mix. Despite how exciting @reubenski has made the round sound I find it hard to keep charging forward with another wildcat that in my humble opinion might be the best sa magnum.
Yeah, I couldn't bite on 25sst and am in the process of a 25 saum. It may be a one off barrel, I saved some coin because I have saum brass and dies. Step down to SST next go, this 25 saum is serious overbore shit, and I am struggling with powder choices. I made the case and bullet in QL, and think I am close, but this could be one of the dumbest decisions I have made, and that is saying a lot, lol
 

charnicus

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Yeah, I couldn't bite on 25sst and am in the process of a 25 saum. It may be a one off barrel, I saved some coin because I have saum brass and dies. Step down to SST next go, this 25 saum is serious overbore shit, and I am struggling with powder choices. I made the case and bullet in QL, and think I am close, but this could be one of the dumbest decisions I have made, and that is saying a lot, lol
Don’t blame you there. Once you factor in the dies, brass, etc. a new round gets spendy. I think the 25 saum would be a straight ripper and fun project. Even if the barrel last < 1000 rounds. Haha