Need Help with CB in 6.5x53R

[fjrdoc]

Hello All.
I've been reloading rifle and handgun cartridges for about 15 years. This includes jacketed and cast projectiles. I have great success with cast boolits in calibers that include: 380, 9mm, 32 and 45 handguns as well as 8x56, 9x56, 9.5x56 and 45-70. However, I'm having a tough time with cast boolits in my 1893 George Gibbs Steyr stalking rifle in 6.5x53R. I originally tried using the Lee 140gr flat nose boolits and then had my first experience with keyholing at 50 yards. I then slugged the barrel and found out that it measured .268 diameter.
I purchased a NOE mold that puts out 160gr boolits that measure .270 diameter. I sized these gas check bullets at .269 and tumble lubed with Alox. I loaded up a ladder of IMR 4350 and headed out to the range today. At least I didn't have keyholing, but accuracy was about 5 inches at 50 yards. Ugh!
I thought that I would see if anybody on the forum might have some insight to help me with this trip down this rabbit hole.

[Larry Gibson]

"I loaded up a ladder of IMR 4350 and headed out to the range today. At least I didn't have keyholing, but accuracy was about 5 inches at 50 yards."

That's the problem, you are pushing them way too fast. IMR 4350 may be a fine powder in that cartridge with jacketed bullets but it really isn't suitable for cast. I'll assume the barrel has a 1 - 7.5 to 7.8" twist as was common with such 6.5s back in the day. You don't give the load but the 5" groups at 50 yards indicates what ever the load(s) were are pushing the velocity and, hence, the RPM well above the RPM threshold.

If so, then you'll want a load with a faster burning powder in the range of Unique thru RL7 that gives a velocity of 1400 - 1700 fps. That will keep the RPM down arounde 130 - 140,000 +/- RPM.

[fjrdoc]

Thanks for the response Larry. I have a variety of powders at home including Unique and RL7. I will load up a couple of ladders and try them out. I just got a Labradar to help with load development.

[Ajohns]

Best load I have in that exact round is 10grs of Unique. 160gr at .269 size.

[fjrdoc]

Thanks Ajohns. I'll need to get down to the lead pot and get some more made. Right now, I'm working on a jacketed load because I want to take this old girl out into the PA woods for deer this year.

[fjrdoc]

Ajohns, do you have an idea of velocity for that load?

[Ajohns]

No, but I would presume 1400fps, maybe more. Seems a lot get in that area in 6.5x55. The 53r is a little less capacity by case volume.
At 40/50 yds it would put a lot of shots in right around an inch. Rear sight set at 500 from its lowest setting of 300, put them just high of bullseye at that range.

[fjrdoc]

Thanks for your input guys. This will give me a good place to start with load development.

[fjrdoc]

I made 3 loads of 10gr Unique and 160gr boolits and had a chance to test them on the range yesterday. Not a bad grouping with no evidence of keyholing. This will give me a good place to start playing around with load development. It sounded like I was shooting a cap gun.

[Ajohns]

Great news!

[Gobeyond]

I tried a 120 gr pointed .260 bullet and paper patched it to .268. Probably wouldnt do that now. No luck. With some paper patch but not all getting them into the case. Was shooting Varget and imr4895. Some 2 inch groups close in with jack bulls. Especially a 120 grain Hornady sp ,pb.. they were cheaper back then. I think I got them up to 1600- 2200. It was fun but didn’t light my cigar.

[15meter]

Tomorrow I'll dig out my 6.5x53R/6.5x54 loads(if I'm still alive, questionable after a morning at the varmint match and the ensuring after match festivities. The wife is passed annoyed) I've loaded a fair amount in these caliber(s), most were in the 140 grain range. Maybe some 170 Lee cruise missile stuff.

If I survive the night.......