6,5x68S Load developement

[Corjack]

I have had this 6,5x68 barrel for my R93 Blaser for about 6 months, finally got enough stuff together to start load development.

Test was done with 120 grain Remington bullets seated just off of the lands using RWS brass. I did not measure the overall length but the loaded round was the max length that fit in the magazine well. The long slope of the shoulder made the rounds feed slicker than snot on a doornob through the R 93 Blaser.All shooting was done at 100 yards.



I started with 60 grains of IMR 7828 SSC velocity was 2779 fps and yielded this 1.5 inch group



62 grains was 2884 fps
63 grains was 2949
64 grains was 3049 with a slightly sticky bolt

7828 SSC yielded one group of around an inch but most were 1.5 to 2 inches

I then switched to Hogden Retumbo and things got a little better



Retumbo powder has very sharp and square cut ends and bridges badly in my Redding powder measure. A friend had borrowded my funnel and trickler and forgot to return it so I only did four loads consistancy of the groups and velocity was not good also velocity was low and smoked the heck out of the cases. This powder looks promising and I will try it again when I have retrieved my loaned out stuff

Retumbo
60 grains 2506 FPS
61 grains 2577
62 grains 2662
63 grains 2692

Here is a picture of loaded rounds and a smoked up case from the retumbo powder



Next I loaded up 58 grains of N560 and got this group



I tried 59 grains of N560 and had signs of pressure and it blowed the group out to nearly 3 inches.It was getting dark so I called it a day. I will continue my testing tommorow and post more information.

Here is a picture of a large snake that had shed it skin in the tree that holds up my target stand.

[Mossberg]

Hi Corjack, nice pictures!

By the way, just out of curiosity since I'm a handgunner myself, do you own any of those?

Mossberg

[Stefan.K]

Seemes like you don´t get a lot of velocity out of the big 68 case!? I would have expected well over 3000 fps with 120 gr bullets........

The 120 gr Remington bullets can´t be seated far down the neck in the cases? I would consider to try a bit more tension on the bullet by seating it a bit deeper in the neck. With bullets seated that far out in the neck there could be some erratic behaviour on the target........

By the way! Retumbo means thunder in a african langauge, may be swahili? I met a guy that worked on Hodgdon back in 2001 name Ron Ribes and he told me the story about Retumbo and where the slow powder got it´s name Ron used to work for Hornady but had just started to work for Hodgdon when I met him in Australia where he was hunting pigs with a friend of mine that work for the Aus. powder mfg. ADI that make most of the riflepowders for Hodgdon.

[Håkan]

I am to surprised by the velocities.
I use to fire a 120 grain bullet från 6,5x55 AI with 3150 fps (probably not low preassure...........)
Used around 54 grains of withavuori N560 at the time.

Regards Håkan

[Corjack]

Am working with H1000 today and things are starting to come together. The only change I have made is to screw in the RCBS seating stem 1/2 turn in to test Stefans case neck tension thoughts.
60 grains H1000 and 62 yielded smoked up cases and poor groups of about 2.5 inches also the velocities were way too low but at 64 and 66 grains it started to come together.





My target velocity is 3100fps and 1/2 MOA groups and it looks like H1000 is going to do it. It has gotten to hot to shoot so I will load up a few rounds with 67 grains and 68 grains to shoot this evening.

I was going to post some pictures of the neighbor lady sunbathing but Mr. Mossberg wanted to see handguns



Will post more results tonight.

[Mossberg]

Unfortunately there's no good-looking ladies besides my wife around where I live, and a picture of her is probably out of the question...
So here is some of my little darlings instead!

[Corjack]

Nice handguns, I only have one Ruger and it is a single six in 32 H&R magnum.

[Corjack]

I continue to work with H1000, am up to 71 grains now. It seems like a good stiff load but not excessive with the pressure. I ran out of the Remington and had to backtrack a little and start up with Sierra 120s and they seem to be a little more accurate. My load with 71 grains of H1000 is hovering around 3/4 inch and I am getting an average of 2179 FPS. this is plenty fast enough for me and as the RWS brass is awful hard to come by and expensive in my neck of the woods I am going to hold right there and work on tweaking the bullet seating depth for a little better accuracy. Here are some numbers on the load I am using now.

Trajectory Output Input Data Manufact ... 19.6

[Internationelle Mats]

Hi Corjack! I'd like to see the bullets deeper still, euro rounds like the x68 aren't throated like you american stuff (freebore + sharp throat) but rather with just a long, sloping throat that doesn't seem to need - or want - bullets close to the lands. Like Stefan said, you'd probably get some erratic groups and/or velocities, especially with the slower powders.

My loads with the 6,5x55 and 7x57, who are throated in the same manner, have bullets seated 2.5-10 mm (.10" to .40" - nope, not a misprint...) off the lands and shoot great. Very few are actually closer than 5 mm (.20") to the lands.

Push 'em down deep and accuracy will be thine, for eternity - amen.

-- Mats

[Corjack]

I am working with bullet seating depth now that I have found a load that seems to be consistant.I will hopefully find the sweet spot in the next few days.

[Corjack]

I am finally able to come to a good stopping place, I dinked around all day yesterday with H1000 and the best groups I could get were 3/4 inch aproximately. I kept pushing the bullet further and further down in the case and when groups gradually opened up to 3.5 inches I quit and lengthened them back out and groups went back to 3/4 inch. so this morning I switched to H4831SC and started at 58 grains, it would put two together and throw one out until I got to 62 grains and then I started getting sub 1 inch groups again. when I went to 63,64 and 65 grains it really came together as you will see in this photo.



Off to the right is a group that measures .700 that the computer cut off.

I then let the barrel cool and fired three rounds through the chronograph and got

3151 fps
3160
3157

giving me an average of 3156 FPS. I am very pleased with this round but the large case capacity did give me fits. As I am not used to loading this much powder.

Another note of interest is the recoil, the round loaded with 71 grains of H1000 recoil is rather sharp with a MV of 3179 however loaded with 65 grains of H4831SC and a MV of 3156 recoil is noticably less.

Overall this has given me a positive feeling for this round and I have fired around 165 rounds through my barrel in 3 days.

I do not feel it is as inherantly accurate as the 6.5x55 but gives plenty good enough accuracy for hunting for me.

Thanks for everyones input on this, your thoughts are always welcome.

Ron Williams