243 Win,,105 Scenar,,RL26 load workup

[Eric Leonard]

I had TClaunch rechamber an old Krieger .236 4 groove 8 twist 6 BRDX bbl to 243 Win with a throat long enough to seat the 105 class bullets with none of the fat part of the bullet below the neck shoulder junction,,over all length with the 105 Scenar seated .020 off the lands is 2.885,,

when rechambering he cut the tennon off and started over so the bbl is now around 27.2 inches long,,

I started loading one round at a time at 46 grs RL26 and WW WLRM primers,at 48 grs I got slightly flattened primers and at 49 grs they were pretty flat but still no heavy bolt lift,,50 grs is too much and I erased the eading of that shot off the magnetospeed screen just so yall wont think I am completely crazy,,

the readings on the screen are for

46
47
48
49 grs of RL26 and 105 Lapua Scenars ,,one shot at each charge,,

I went back and loaded 5 rds at 47 and 47.5 and shot for group at 100 yards without chrono attached to bbl to get a good zero and idea of accuracy at these speeds,,the 47.5 gr load was .385 inch 5 shots at 100 yards,,

gonna try that at 600 now and see how it goes,,seems a 105 at 3300++ would be a lazer beam,,but gonna shoot it some and see how everything holds together,,

wish me luck as I am sure it wont last long,,LOL

 

[tbeasley]

Holy crap that's fast!!! Keep us posted, like to see where you end up on that load/rifle combo.

 

[Changeling]

WOW, I'm actually surprised at those speeds for 105 gr bullets, they look like 6mm Remington velocities 8)

 

[Eric Leonard]

I loaded 25 rounds at 47.5 grs and went to 600 yards,,it was only 8.5 moa trip from 100 yards,,,but as rifle started to get hot about 12-13 rounds in it started getting a little ejector swipe and by the time I shot 20 rounds it was starting to get a little heavy on the bolt lift right at the top,,probably 46-46.5 at 3225 fps will be max for sustained fire with this powder,,I didnt go take pics of target after seeing load is too hot but it was making one big splatter on steel plate at 600 about like a baseball,,I dialed up to 1,000 and shot last 5 rounds just to see and it only took 19.75 moa to make 1,000 from a 100 zero,,I may be asking too much but would like a good accurate load that will not lock rifle up at about 3300 fps,,going in I was more worried about bullet failure but that isnt gonna be an issue with the Scenars,,

I am gonna try H1000 ,IMR7828 and H4831 next,,

 

[ShootDots]

I loaded 25 rounds at 47.5 grs and went to 600 yards,,it was only 8.5 moa trip from 100 yards,,,but as rifle started to get hot about 12-13 rounds in it started getting a little ejector swipe and by the time I shot 20 rounds it was starting to get a little heavy on the bolt lift right at the top,,probably 46-46.5 at 3225 fps will be max for sustained fire with this powder,,I didnt go take pics of target after seeing load is too hot but it was making one big splatter on steel plate at 600 about like a baseball,,I dialed up to 1,000 and shot last 5 rounds just to see and it only took 19.75 moa to make 1,000 from a 100 zero,,I may be asking too much but would like a good accurate load that will not lock rifle up at about 3300 fps,,going in I was more worried about bullet failure but that isnt gonna be an issue with the Scenars,,

I am gonna try H1000 ,IMR7828 and H4831 next,,

I wonder if at those velocity levels, under sustained fire, as in an F-Open match, would not cause bullet failure and explode those Scenars? That is a real possibility..

 

[Eric Leonard]

I shot those 20 rounds in about 15 minutes and they all made it to target,,I am gonna try H1000 next and see if it will get where I want to be,,

how long does it take to shoot a 20 shot string in an F Class match,,when I get a load I will shoot 20 rounds to mimic FClass conditions and find out if they will take the strain,it may well be more than they can bare,,

 

[racesnake]

Hi, Ben...I sorta did the same as you. I rechambered a burned out 6X47L to 6SLR which is equivalent to a 243 capacity wise. The last load I tried gave me 3307fps ave. I went up from there but started to get a little gas leakage around the primers. I was using Berger 105 BT's and IMR 7828SC. You might want to give it a try.
Dave

 

[Eric Leonard]

7828 was next on list behind H1000 but I can move it up and try it next instead,,

how long is your SLR bbl ??

 

[racesnake]

Barrel length approx. 29". I didn't have much luck with H 1000. ES was too high.

 

[Eric Leonard]

mine is 27 1/4 ,,I will try the 7828 next but with shorter bbl may back my goals down to 3200 or so,,

I wonder what the pressure was on that one shot that hit 3400, ???

 

[KD185]

TAG

 

[ShootDots]

The only reason I was wondering is because a friend of mine (Smoking-Brass) on here has a .280A.I. he uses for F-Open. He was running 180 Scenars somewhere a bit north of 2950. I THINK (not sure) that he was in the midst of his second match, somewhere around shot 10-15 and they started blowing up. Once the barrel cooled down to SOME DEGREE, the bullets stopped that behavior. But once again, as the barrel heated up, the Scenars were smoked in mid-air.. I would not want to see someone get into a match and go thru that experience. It would be well advised, during the summer especially, to run the barrel hot for a shot string or two to make sure that anomaly does not exist.

 

[KD185]

The only reason I was wondering is because a friend of mine (Smoking-Brass) on here has a .280A.I. he uses for F-Open. He was running 180 Scenars somewhere a bit north of 2950. I THINK (not sure) that he was in the midst of his second match, somewhere around shot 10-15 and they started blowing up. Once the barrel cooled down to SOME DEGREE, the bullets stopped that behavior. But once again, as the barrel heated up, the Scenars were smoked in mid-air.. I would not want to see someone get into a match and go thru that experience. It would be well advised, during the summer especially, to run the barrel hot for a shot string or two to make sure that anomaly does not exist.

you wouldnt happen to know what powder he was using?

 

[Titan700]

Following

 

[ShootDots]

The only reason I was wondering is because a friend of mine (Smoking-Brass) on here has a .280A.I. he uses for F-Open. He was running 180 Scenars somewhere a bit north of 2950. I THINK (not sure) that he was in the midst of his second match, somewhere around shot 10-15 and they started blowing up. Once the barrel cooled down to SOME DEGREE, the bullets stopped that behavior. But once again, as the barrel heated up, the Scenars were smoked in mid-air.. I would not want to see someone get into a match and go thru that experience. It would be well advised, during the summer especially, to run the barrel hot for a shot string or two to make sure that anomaly does not exist.

you wouldnt happen to know what powder he was using?

Yes I do.. He was using Retumbo when the Scenars went to pieces..

 

[jpretle]

I wonder how rough the bbl was, in that 280??? Maybe that had as much to do w/ the 'blow up', as the heat.

 

[ShootDots]

I wonder how rough the bbl was, in that 280??? Maybe that had as much to do w/ the 'blow up', as the heat.

It was (he still has it) a brand new McGowan...If he keeps them around 2850f.p.s.>>>no trouble.. BUT his barrel is a "straight" 1-8 twist.

 

[racesnake]

Went back and re-tried the 7828 load the gave me the 3307fps. This time I had 2 blown primers. I'm gonna try dropping back to 3200 - 3250 and find a node I can live with! I'll keep you guys posted.

 

[MOShooter]

I've tested H4831, H1000 and RL26 in my 6slr with 105 hybrids. The 26 was about 180fps faster than both the other powders. That stuff gets some mega speed in the 243 case. However, it did seem to spike the pressure if it got hot.

Scott

 

[Frankr]

I loaded 25 rounds at 47.5 grs and went to 600 yards,,it was only 8.5 moa trip from 100 yards,,,but as rifle started to get hot about 12-13 rounds in it started getting a little ejector swipe and by the time I shot 20 rounds it was starting to get a little heavy on the bolt lift right at the top,,probably 46-46.5 at 3225 fps will be max for sustained fire with this powder,,I didnt go take pics of target after seeing load is too hot but it was making one big splatter on steel plate at 600 about like a baseball,,I dialed up to 1,000 and shot last 5 rounds just to see and it only took 19.75 moa to make 1,000 from a 100 zero,,I may be asking too much but would like a good accurate load that will not lock rifle up at about 3300 fps,,going in I was more worried about bullet failure but that isnt gonna be an issue with the Scenars,,

I am gonna try H1000 ,IMR7828 and H4831 next,,

mr.big do you think you started to show pressure due to HOT chamber barrel or barrel fouling or both? If you let it cool would the load still show pressure ?
Be careful with IMR7828 only time I had shot it, was in a big mag, it showed no pressure signs at all then I went up 1/2 gr of powder and it stuck the bolt I barley got it open and wrecked the brass case. 7mm WM Norma brass Mark V..
what really scared me about it was I have never not had some kind of warning that I was starting to get hot but I did not and a 1/2 gr of powder in a case of that capacity is not much..but shot the load everything looked good went up 1/2 gr went off fine nothing unusual but the bolt would not move, I got it open but almost did not..the case was flattened surprised I did not blow a primer.