Anyone shortened the 6.5-284
- Thread starter bradb
- Start date
I did about 25 years ago or so. Of course we didn't have the 6.5-47 Lapua then but I was tired of everyone saying that the only accuracy node was 2950 fps when the case could support a better velocity than that. This was also before the QuickLoad cartridge drawing software for wildcatters. I solved it by using geometry and cubic area in CCs.
I don't remember the exact length but my goal was to get the capacity down to about 55 grains of H2O. It seems that 1.9" is about right but I'll have to get those cases out of storage along with the load data. I machined dies to push the shoulder back in steps. I bored the chamber because I didn't want to have to pay for a reamer. All-in-all it turned out nicely if I remember correctly.
I got into a discussion with Larry Bartholomew when he asked this same question at about the same time so I gave him the dimensions I was using and he made some brass but I don't know what happened after that. It may not have performed up to his expectations.
I'll see if I can find the brass and notes so I can relay accurately what I did.
Regards.
O.K., long hot search through a ton of older notes and case development projects but I found what I was looking for.
I initially shortened the case to be 1.800" in it's final form. I made one master die body and 3 different tops which I interchanged to gain the proper shoulder and body length. Obviously I had to fireform the cases then cleaned and trimmed to final length.
The net case capacity is 50.5 grains of water averaged between the 10 cases I finished. This is the case capacity of the .250 Savage Ackley Improved based on the notes.
My notes have a velocity range of 2850 - 2925 FPS based on using the Norma 130 VLD which I picked up from Norma at the SHOT Show that year, and which powder I tested. It's basically a 4350 case but I got the best performance from H-414 and VVN-550. This from a 26" Krieger barrel which was 4-groove.
The final iteration was a finished case with a length of 1.900" and case capacity of 53 grains of H2O which is similar to the 260 Rem. Here I could achieve 2950 fps. from the same 4350 powder slightly compressed but I could also push it up to approximately 3000 fps. with a hotter powder.
That's the basics!
Remember when you shorten a case it turns into neck . The problem is the neck is thicker after . I have made plenty of 6mm Remington brass out 06 brass . Larry
Yes, yes, yes. I had a small watchmaker's lathe at the time which I left set up just to turn necks.
Jason Boersma
Silver $$ Contributor
Just use the 6.5x47L case and push the shoulder forward .100 and use a lot freebore and you can push a 140gr to 2950 easy. This is the cartridge I shoot in LG and HG at 600 and 1000 and it works.
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I took the case and shortened it to seat a Berger 130 at 2.80 oal last winter.What was strange these cases are supposed to like h 4350,this one shot re 22 the best go figure?
Re-form 308 Win small primer Lapua 'Palma' brass into 6.5 Creedmoor or 260 (preferably 40-deg AI) and you have a 6.5X47L 'improved'. Sure, it doesn't have as fat a case-body as the 6.5-284, so the powder column will be slightly longer than that of a cut-down 6.5-284, but I doubt if you'd notice the difference in performance in a good chamber and barrel. In 6.5 Creedmoor you get around 52gn water capacity with reformed Lapua, in straight 260 55gn, and AI what ? maybe 56.5/57gn?
Vince Bottomley who has held the UK BR Assoc 1,000 yard 'Light Gun' small group record for many years has been one who's played with 6.5-284 off and on for a long time, not to mention burning out a couple of barrels in 6-284. Having decided that the cartridge case has a bit too much powder capacity (the 6.5X55 40-deg Imp being his ideal) he did some serious body reforming on the cartridge to shove the shoulders back enough to get to the 55AI case capacity. It worked, but he says the improvement was so marginal that it didn't justify the work.
Vince Bottomley who has held the UK BR Assoc 1,000 yard 'Light Gun' small group record for many years has been one who's played with 6.5-284 off and on for a long time, not to mention burning out a couple of barrels in 6-284. Having decided that the cartridge case has a bit too much powder capacity (the 6.5X55 40-deg Imp being his ideal) he did some serious body reforming on the cartridge to shove the shoulders back enough to get to the 55AI case capacity. It worked, but he says the improvement was so marginal that it didn't justify the work.
Which is the same reasoning I used in my response.
We didn't have the Creedmoor cases or the 6.5x47L case for that matter 25 years ago.
That's why I still only have the same 10 original cases which I made to conduct the original experiment. The performance was as expected but there are other alternatives which require next to zero work to accomplish the same goals.
It was fun, I learned a lot but I got over it and moved on.
Regards.
That's about how many I have left,I was getting flashbacks from my stupid 338 case,and came to the same realization you did.
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