In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
6.5 - 284
Alan Rushing
Member Posts: 8,805 ✭✭✭
Hello everyone,
Would you folks that have worked with the 6.5-284 and it's variants share your experiences and your insights?
If you have played with or tweaked the chamber dimensions here or there, I'd like to hear of that also!
Thanks, Alan
Would you folks that have worked with the 6.5-284 and it's variants share your experiences and your insights?
If you have played with or tweaked the chamber dimensions here or there, I'd like to hear of that also!
Thanks, Alan
Comments
I'm glad to see that you made it back.
The 6.5-285 is similar to the 6.5-06 and the 6.5x55 Improved. If you take the time to correlate all the competition data from the shooters using these cartridges, you'll see a lot of overlap.
The 6.5x284 cartridge is very nearly an ideal cartridge so long as you are aware of some of the potential drawbacks. Also be aware that there is a difference between some reamers. The Norma version has a longer throat to allow the really long bullets to be seated out.
The case capacity is in the range of the venerable '06 case so there is almost too much of a good thing when it comes to powder capacity and available heavy bullets suited to this capacity. In fact, there are many shooters (JustC is one that comes to mind) who have used and competed with the 6.5-06 case in it's original form and the Improved form. He can certainly add a lot to this discussion from this standpoint. I switch back and forth between the 6.5 x 55 Swede and the 6.5 x 284.
The reality of the capacity situation is that the cartridge would benefit from a little less. The most vocal of the target shooters using the 6.5-284, contend that the best accuracy node is in the 2950 FPS range give or take a tad. This as a result of much testing and a desire to maintain some decent barrel life to conserve dollars. So I've shortened the case a little and I've shortened the case a lot, in a range of just about 61 grains down to 56 grains. With judicious testing and only using the longer, heavier bullets, I got down to the magic velocity number as suggested. Low and behold, there is an accuracy node there and it's a good one! But it's certainly not the only one so I went back to the original case and switched powders to an earlier tested combination.
Now I find that I am at the next higher node for velocity which is somewhere around the 3075 - 3100 FPS. I'm running a slightly slower powder with a slightly longer barrel at a slightly lower pressure and hitting the slightly faster node. I've also switched to a different rifling form which appears to be a little faster than other barrels I'm testing. This is a hard call to make though since there are a tremendous number of variables and factors that can play a role in velocity.
Barrel life will be the question to satisfy for most shooters but I don't factor that in unless that number happens to fall at some inopportune point in a competition season. I prefer to make it through the season before I have to change barrels. Now though, I'm just as likely to switch rifles and finish up if I sense a fall off in accuracy then switch out the barrel when it's convenient.
The case configuration has stayed the same for my testing except for the shortening of the case. The 35 degree shoulder works for me as do the dimensions. Minor changes could make very subtle differences but may be too subtle for absolute qualification.
A few of us are running a program with one cartridge (not the 6.5-284) and changing the shoulder angle by one degree at a time, from 30 degrees to 40 degrees, while shooting a full battery of tests at the range for each. Imagine doing a load ladder for each of several powder/bullet combinations for 10 shoulder angles. So far it's a toss up because of the lack of data. It would be nice to have a ton more data but time and materials are mounting and we're just not seeing the justification.
We're seeing the reports from 'independent' shooters who are showing data and targets that seem to demonstrate improved consistency and accuracy from a slight angle change in shoulder, from let's say 30 degrees to 32 degrees. We're also seeing more finessing of the case capacities for improving consistency in many of the short action cartridges. This is encompassing the 6mm and 6.5mm cartridges but will have a trickle down effect on the .22 caliber as well.
I have work to get back on so this will have to do for now.
Best.
You will find the sweet spot between 2900-2950FPS in my experience.
First 4 shots from a clean barrel and subsequent "dial in".
JustC, how often do you get out to play with your 6.5x55AI? How long have you had it and how much shooting with it to date? I appreciated being able to see the evidence! Thanks for sharing about it and the 6.5-284, appreciated.