.243 Super rockchucker loads??

[DavidPatton]

Hey guys Im very new to the hand loading game and in desperate need of some help. I have a 243 super rockchucker that im trying to get dialed in but finding load data is nearly impossible. From what i know it is a 25-06 necked down to 243. The loads that came with the gun are 70 gr. nosler, with 55gr imr 4350, case length- 2.494, and total length- 3.175. These round are not accurate at all, and the best i could get is a 1.5in 3 shot group at 100yds. We experimented this weekend with trying different amounts of powder and got down to a penny size group, but still not very happy. Also the bolt is hard to close like the total length may be to long. the only data i have is what came with the gun. It also had a box of barnes bullets, and two serria boxes with it but im not sure what they are yet i havent weighed them and the boxes are in rough shape. Any input would be awesome! thanks

 

[korykhunter]

If this is also known as the 6mm-06 Handloads.com may have some loads. I know nothing about this cartridge and had to do a quick search.

 

[Fuzzball]

All any manual can be is a guide for you, none are scientically precise. You can use .240 Weatherby loading data, they're effectively the same cartridge. With that huge case your best efficency will be with heavy for caliber bullets like 90 - 100 gr. If you can get sub .750 MOA with an over-bore cartridge like that you're already doing great.

 

[BuzzBoss915]

I agree, three shots under a penny is more than satisfactory for that cartridge. I would weigh those Sierra bullets, for sure and probably not use the Barnes, at all as they sometimes won't seal properly in the bore and (anyway) they are supposed to be a solution to a non problem/lead contamination of the environment.

For sure, get some data and find out the max. overall length; your brass is likely in need of neck trimming. case length- 2.494" is all well and good, but the specs are available somewhere and you need to know it.

4350 may be satisfactory, but if you want to try something else, H4831 might be a better choice, depending on your bullet, of course. BB

 

[DavidPatton]

thank you guys for the advice. I am going to find some specs before we do anymore shooting. Unfortunetly i have not been able to find a diagram with overall length, but havent given up just yet.

 

[Rmitch223]

Give they 105gn Hornady Amax bullets a try with H4350.

 

[DavidPatton]

Give they 105gn Hornady Amax bullets a try with H4350.

will try that and see how it works. Thank you for the help.

 

[1lnbrdg]

What twist is your barrel? It will probably take a 1/8 twist to shoot the 105~108gr bullets.

 

[Fuzzball]

"...i have not been able to find a diagram with overall length, but havent given up just yet."

Don't worry about it. You have to reload for your rifle, not a diagram.

Find the max length for your bullet of choice that reaches the lands and start about 20 thou deeper than that. Or at the max length your magazine will allow without jamming your bullet into the lands. Start low with a powder charge and slowly test for accuracy as you work up to what ever data max you choose OR until you see signs of excessive pressure earlier. If that happens drop back maybe 5% and call it your max safe charge for that load no matter what the data says.

With light or mid weight .24 cal. bullets one of the 4350s should be good. If you use 90+ gr. bullets a 4831 should work better. Or something else within the same burn rate range. A 1:10 barrel should shoot 105 gr. bullets fine if you load to normal pressure/speed for that cartridge.

After finding your best shooting charge, try a few more tests by seating deeper in perhaps steps of 10 to see if you can tweak the accuracy.

 

[DavidPatton]

"...i have not been able to find a diagram with overall length, but havent given up just yet."

Don't worry about it. You have to reload for your rifle, not a diagram.

Find the max length for your bullet of choice that reaches the lands and start about 20 thou deeper than that. Or at the max length your magazine will allow without jamming your bullet into the lands. Start low with a powder charge and slowly test for accuracy as you work up to what ever data max you choose OR until you see signs of excessive pressure earlier. If that happens drop back maybe 5% and call it your max safe charge for that load no matter what the data says.

With light or mid weight .24 cal. bullets one of the 4350s should be good. If you use 90+ gr. bullets a 4831 should work better. Or something else within the same burn rate range. A 1:10 barrel should shoot 105 gr. bullets fine if you load to normal pressure/speed for that cartridge.

After finding your best shooting charge, try a few more tests by seating deeper in perhaps steps of 10 to see if you can tweak the accuracy.

Awesome! That is basically what i am planning on doing. The guy i got it from was not really sure how to load for it so it turns out that some of the test loads we had were not properly loaded. I am taking all the bits and pieces that came with it to a buddy that builds custom gun tomorrow and we are going to start from square one. Thank you all for helping me out. The barrel is a 1:10 twist.

 

[armorpl8chikn]

I probably know the guys you got the rifle from. Used to shoot at Hawk's Ridge with some guys that used the SRC.
I would try H4831SC...if I could find any data. Data is pretty hard to find for that one though as you can see. Penny sized groups with that rifle ain't nothin to sneeze at, it'll do. I would find out what twist it is as soon as possible. Most of the guns I know of in that caliber are 1-8 but if you got it from a ground hog guy it is likely 1-10 or maybe even 1-12.
I wish you luck and hope you settle on a load quick. This one is a known barrel killer.

 

[DavidPatton]

It is a 1:10 twist, and im not sure the of the guy who built it, but he sold it to a friend of mine. At that moment all info was lost because he just gave my buddy two boxes of loaded ammo instead of giving him all the load data. We are on the right track to getting it dialed in, im just freaking impatient because this is my first long range gun

 

[Rmitch223]

It is a 1:10 twist, and im not sure the of the guy who built it, but he sold it to a friend of mine. At that moment all info was lost because he just gave my buddy two boxes of loaded ammo instead of giving him all the load data. We are on the right track to getting it dialed in, im just freaking impatient because this is my first long range gun

The 1:10 twist will not stabalize the 105 gn and up bullets.
look at 55-87 gn bullets

 

[BuzzBoss915]

Kinda depends on what 105 gr bullet. I have a M600 chambered in 6MM Rem (slightly different twist) and it's a decent mountain mule deer rifle with 105 gr. Speers. As long as the bullet has a longer bearing surface it should stabilize. But, the faster you drive it, the more RPM and the more likely it will be accurate with target bullets. Yeah, it will be a barrel burner, about like a 6/284, which means it's better suited as a hunting rifle rather than targets. BB

 

[DavidPatton]

the two loads he had a little info on were 70 grain noslers and 88 grain bergers. i will stay in that range and try to find what it likes. I bought it to be my target gun, and i know it will be a barrel burner but i got a steal on it so after i burn out the barrel i will still have some good parts and not a whole lot invested lol