6.5x55 imp?

[moondog]

Thoughts and comments on 6.5x55 Swede. Accuracy? Just thinking.
It will be a Tacti cool rig. I am spoiled by Accuracy though and wouldn't do it if it is a finicky hard to tune cartridge.

 

[Laurie]

There is an argument that the 6.5X55 AI (and similar case-capacity 6.5 wildcats based on the case) are the ultimate cartridges in that calibre. The straight 6.5X55 struggles to get enough powder = energy into its case, the next size up, the 6.5-284 in the view of some has a greater capacity than needed to get optimal MVs from the highest BC bullets. The 6.5X55 AI slots into the gap and is ideal - 100% fill-ratios for ideal MVs. Using QuickLOAD's default case capacities, it is 57, 62, and 66 gn water for the straight Swede, AI, and 6.5-284. I suspect the 5gn increase for the AI over its parent case overstates the improvement, but (like the 7X57mm) this is an example of where 'improvement' gives a large enough capacity increase to be really meaningful.

Since that time (say 10-15 years ago), new high-energy powders such as Re16, Re17, and Re23 have appeared that may have changed things, likewise match bullet weights no longer have a 142gn upper ceiling. Nevertheless the AI version has a lot going for it.

In the early days of F-Class when 6.5s ruled, the 6.5X55AI had a fair few followers. The 6.5-284 soon blew it out of the water though .... but at the cost of a significant decrease in barrel life. I considered the cartridge seriously at one point but ended up going for the straight version. At the time, there were no dies available other than very expensive custom ones. A commonly used 'fix' was to take the 6.5X55 Redding Comp dies with their internal case-holder sleeves and 'rechamber' them to the AI version, the sleeves being soft and easily machined.

 

[moondog]

Accuracy is my first and foremost interest.
Yes, new bullets and powders make it an interesting case to look at with barrel life better than 6.5x284

 

[Laurie]

Accuracy is my first and foremost interest.

They (straight 6.5X55, the AI version, and 6.5-284) are ALL capable of outstanding precision. They have all produced long-range successes in BR and F-Class. Same with the smaller 6.5s too. I doubt if you could prove one way or the other that the 6.5X55 AI is superior/inferior to the other pair. It does give more performance than the straight model without running silly pressures and with less taper needs a lot less case-trimming. Some would argue that the 40-degree shoulder makes it 'more efficient' = 'more accurate'. Personally, I've never been the least bit convinced by this argument.

An excellent cartridge. I'd still have a go with it if dies were as easily obtained as those for some other improved models, eg the 7mm Shehane.

 

[Bbear]

I like the accuracy I get from my hunting rig; Model 70 action, Pac-nor 22" barrel. 2800 fps with IMR4350 and the 142 ABLR.

Can't imagine how much tighter it could get in a full-on F-class or other target rig.

 

[kyreloader]

150g SMK, 6.5x55 BJAI from my PRS/hunting rifle at 300 yards-long action Ruger M77 build.

Love my 6.5x55 BJAI.

 

[Liven The Dream]

I have been happy with my 6.5X55 with 32 “ R-5 Barrel in a 1000 yard probe rifle.
140 Bugers at 2900 + do ok

 

[Mulligan]

What’s the difference between an 6.5x55AI and the BJAI?
CW

 

[Evlshnngns]

My BJAI will push a 140 nosler c.c. 2950fps with 49.5gr h4831. I have pushed it to 51 without a problem. I don't think you can expect 6br easy tune, but it should be roughly the same as a 260ai or 6.5x.284.




edit: 26'' barrel

 

[JRR]

6.5X55 SE with 28" Krieger. 147 with Rel26. I'm getting 2840 fps for my max load. Excellent accuracy.

 

[1shot]

I shoot a 6.5 GWI and it is based on the Swede. 30* sholder with a H20 capacity of 66.65 gr. It would routinely drive 140 JLK bullets at 3,055 fps. I'm now shooting it with the 150 SMK's at 2,980 fps. Shot this group last week while doing some tuning.
I hope this helps,

Lloyd

 

[Spook]

6.6X55BJAI
my shooting Buddy, Heather, shot this caliber in FClass and 600,1K BR last season.
IMR 7828SC with 147 Hornady ELDM

Its a very accurate cartridge

 

[Ggmac]

I've tried many 6.5s ,including the 6.5 AI swede , I'm stuck on the 6.5 Rem mag with a few changes . Easy to load and tune . Same case cap ( almost ) as the 6.5 -284 . New problem is finding good brass for it .

 

[geraldgee]

What’s the difference between an 6.5x55AI and the BJAI?
CW

Your question piqued my curiosity. I found the following on the web - not sure if its right - to be taken with a grain of salt.

"Bob Jourdan Ackley Improved" or BJAI - Jourdan's version is a blown out case with a 40 degree shoulder and a straight or nearly straight taper.

Gerald

 

[moondog]

Didn't realize this question has been beat so hard. I think with all the past info out there, the 6.5x55 gwi looks to be a proven performer. Or, maybe I should go to the dark side and do a 6.5 Creedmoor!

 

[thekriebles]

What’s the difference between an 6.5x55AI and the BJAI?
CW

Geraldgee above is correct. Here's some additional info on the 6.5x55 BJAI: The late Bob Jourdan developed the wildcat during the early 90's and published it in Precision Shooting March & Aug. 1992. Bob Jourdan adopted Ackley's work to the Swede and named it after himself and Ackley - "Bob Jourdan Ackley Improved" or BJAI. Jourdan's version is a blown out case with a 40° shoulder and a straight or nearly straight taper and it is .010" bigger at the shoulder. Left to right below: factory 6.5x55 Swede, 6.5x55 Imp. 30°, 6.5x55 G.W.I. (Greg Walley Imp. 30°), 6.5x55 Ack. Imp. 40°, 6.5x55 BJAI):

 

[Mulligan]

Geraldgee above is correct. Here's some additional info on the 6.5x55 BJAI: The late Bob Jourdan developed the wildcat during the early 90's and published it in Precision Shooting March & Aug. 1992. Bob Jourdan adopted Ackley's work to the Swede and named it after himself and Ackley - "Bob Jourdan Ackley Improved" or BJAI. Jourdan's version is a blown out case with a 40° shoulder and a straight or nearly straight taper and it is .010" bigger at the shoulder. Left to right below: factory 6.5x55 Swede, 6.5x55 Imp. 30°, 6.5x55 G.W.I. (Greg Walley Imp. 30°), 6.5x55 Ack. Imp. 40°, 6.5x55 BJAI):

View attachment 1058036

That is super helpful, Thank you very much.
I have been pondering a good fuel tank for the 150 SMK, that BJAI may be just the ticket.

CW

 

[thekriebles]

That is super helpful, Thank you very much.
I have been pondering a good fuel tank for the 150 SMK, that BJAI may be just the ticket.

CW

In addition to shooting, I enjoy collecting the cartridges. Seeing them in person has also assisted me in making future chambering decisions as well.

 

[Laurie]

That is super helpful, Thank you very much.
I have been pondering a good fuel tank for the 150 SMK, that BJAI may be just the ticket.

CW

Bear in mind that the rule of thumb for the effect of case capacity change on MV is that all other things being the same (bullet / barrel length / PMax), the % MV change is 25% that of the case capacity % change.

Increasing the standard Ackley upper body diameter at the shoulder by 10 thou' will barely affect the overall capacity, maybe by a mere half-grain water in a fireformed case. Let's be generous and say a full grain of water. As the standard AI holds around 62, 63gn, an extra 1gn = 1.6%. A quarter of that = 0.4%. If the 6.5X55AI can give the 150 SMK 2,900 fps as a guesstimate in a match rifle length barrel, an extra 0.4% equates to 11.6 fps, 12 when rounded. Different barrels even from the same maker often produce greater variances than that! Even if the small difference in case-shape saw an extra 2gn water capacity (which almost takes it to 6.5-284 level) the likely improvement is only 20-25 fps.

If a 6.5X55BJAI reamer and dies are more easily obtained than those of the plain-Jane AI, well and good. If it takes more time, trouble, and money to go that route I for one would need some convincing of its benefits.

 

[Evlshnngns]

In my search the BJAI is pretty common. That is the PTG reamer at grizzly.com and the Redding dies at Grafs are bjai.

Somebody that shoots the 6.5 Addiction needs to send a retired case to Thekriebles, nice collection! I think the 6.5A has a 35degree shoulder, .455 at the shoulder-body junction.