107 Sierra MK .243 in a Shilen 1:8 26" barrel need load help

[mattri]

Just to ge a baseline I loaded 39, 40 and 41grns of H4831sc set just into the lands.

39grns did about 1" @225

40 and 41 shot about .75 @ 225 with the best group of the day being .633.

41grns of H4831(sc) is the max shown in all of my tables, has anyone used hotter loads with better success?

Going to work with seating depths and see if that helps.

I know IMR4350 and others are popular powders, would prefer to stick with H4831sc for now.

[10ring]

What caliber are you shooting?

[mattri]

Sorry .243 win.

[10ring]

Do you use a crono? Can you tell pressure signs. What I usually do is work up loads in small incriments like .3 untill I have some pressure signs then you know where your max is because every rifle is different. I can tell you one thing that in my rifle I have gone over book max with no pressure signs. Another powder to try would be varget.

[mattri]

No pressure signs and no, don't have a chrono yet.

One thing that I noticed about the Match Kings is that I had to seat them much farther out to reach the lands, going to back off a little and see if that helps.

[Elkbane]

Mattri,
Maybe it's just me, but I've yet to have MK's shoot better jammed than jumped, but I've only tried them in two different calibers - 7mm (130 and 150gr) and 6.5mm (142's). Never tried them in 6mm. You may want to try to jump the 10-15-20 thousands and see how they shoot. Glad H4831sc is working for you, it's been pretty consistent for me.
Elkbane

[Joe O]

I would change seating depth,but first sort the bullets with a comparator.It surprised me to find Sie Match kings,as much as .010 difference frome base to ogive,between bullets in the same box.I don't sort by weight,but I would,if I was having trouble getting a custom barrel to shoot,having tried everything else.Try Nosler bullets.

[Elkbane]

Joe, I agree with you - just didn't want to start an "SMK's no good" rant by calling them out. The most consistent bullets I've measured and weighed are Lapua Scenars and Bergers. Hornady AMAX's are pretty decent, especially for the price. The worst are amost always SMK's, although I di have one really decent lot of 7mm SMK 130's . I think that may be why they shoot better jumped for me????? And even then, they shot good enough to tease me into thinking I could fiddle with the load and make them outstanding (but I never could). They were good, but not great.
ELkbane

[mattri]

Great replies, thanks. I didn't know that the MKs had a rep for being that off.

I wanted to try the 105 A-Max but couldn't find any.

[Senderofan]

I would second the seating depth deal. I also found that SMK's liked to jump a little...in my .25-06. For that rifle...I found Nosler ballistic tips to have irregular shapes...and thus I couldn't dial in my load. The SMK's were pretty darn close.

Good Luck...Kepp us posted on your progress.

Wayne

P.S.
You really need to invest in a chronograph....really helps you see when your load is dialed in.

[Joe O]

Great replies, thanks. I didn't know that the MKs had a rep for being that off.

I wanted to try the 105 A-Max but couldn't find any.


DON'T KNOW ABOUT REPUTATION,BUT WHEN MY FRIEND, WHO SHOOTS INFORMAL LONG RANGE COMPETITION, AT THE CLUB LEVEL,QUESTIONED A SIERRA TECH, ABOUT WHY THEY BOTHERED TO CALL THEM ,"MATCH",THEY TOLD HIM,"WELL ALL THE GUYS SORT THEM".HE TOLD THEM TO CALL THEM PLINKERS.THAT'S WHEN I GOT HOME AND RAN MY 95GR mk THROUGH MY COMPARATOR.THE FIRST TWO BULLETS OUT OF THE BOX WERE .009 DIFFERENCE.IIONLY GOT 35 OUT OF 78 THAT WERE WITHIN .002 IN THE MID RANGE.THEY DID PRODUCE .221 OUT OF MY HART BARRELED REMY243AI CUSTOM,BEFORE I MESSED UP THE CHAMBER(DON'T ASK).I GET THE GUN BACK TUESDAY ,WITH A NEW BARREL.A CHRONY ALPHA MASTER,WITHOUT PRINTER,BUT WITH REMOTE,HAS SERVED ME WELL FOR OVER 10 YEARS.THEY ARE NOT MUCH OVER $100.