Home Forums Reloading Big Game Rifles 6.5x55 or 6.5 creedmoor with RELOADS

i have read many threads comparing the two, but everyone always talks about how the 6.5x55 has more room in the case than the factory loads have loaded due to needing to be safe for old guns.
However I can’t ever find any info on what the calibers will do with a 140 when they are maxed out.
Basically, I am going to order a Tikka tomorrow and I can get the gun I want three different ways.....
6.6x55 with a 22.5 inch barrel
6.5 creedmoor with a 22.5 inch barrel
Or last a 6.5 creedmoor with a 24.5 inch barrel.
Personally I like the idea of 22.5 inch barrel but not sure if I’ll lose much speed with the shorter barreled guns. Since I will be reloading, I’m not concerned about factory ammo.

The 6.5x55 case will hold approximately 57.9 grains of water, the .260 case will hold approximately 53.5 grains of water and the 6.5 Creedmoor case will hold approximately 52.5 grains of water. (The precise capacity of different brands of cases will vary, due to different wall thickness, etc.)

Based on those capacities the 6.5x55 has about 10% more case capacity.

SAAMI pressure for the 6.5 Creedmoor is 62 kpsi. The 6.5x55 Swede has approx. 10% more volume than the Creed. Using the 1 to 4 guide - velocity increases at 1/4 the rate of case capacity - you should be able to best the Creed by about 2.5% more velocity at the same pressure. The latest Hornady handbook shows the 6.5 Creedmoor topping out at 2750 fps with 140-143 grain bullets with one load going to 2800. So, if the Creed gets 2750 fps with a 140 grain bullet the Swede should be capable of 2819 fps (2750 X 1.025) in an equal barrel length. You'd have to add more powder to the Swede to get that pressure and velocity (2-5 grains more depending on the powder) but other factors come into play as well - variations in chambers, different components and so forth. So unless you use the exact same components as a published Creedmoor load - and you obviously can't match the brass except for brand - your pressure will be affected in unknown ways.

Those are the numbers but IMHO if you're just looking at velocity you'd be ignoring other factors which put the Creedmoor solidly ahead and that's not counting factory ammo at all since the question is about reloads. The 6.5 Swede typically has very long throats even in modern rifles. I haven't personally measured a Tikka 6.5x55 throat but posts from another member confirm that is is indeed long, plus it is built with their full long bolt throw (they are all built on the same length action with bolt throw dictated by the bolt stop). While the above velocity calculations are based on reliable concepts the velocity figure derived is still an educated guess. And even if everything else turns out right you only get about 60-70 fps more, whereas there is solid pressure tested data for the Creedmoor.

I really like the 6.5 Swede, had two and still have one, but except for some nostalgia and a calculated 69 fps velocity increase the Creed has more going for it in a modern rifle.



Ran some numbers on the Hornady ballistics calculator using a 140 ELD with a BC of .620 in a rifle sighted in at 200 yards, that 69 fps gets .4" less drop at 300, 1.1" at 400 and 2.3" less drop at 500 yards. Using a scope with reliable 1/4 MOA adjustments, at 2819 fps that's 6.16 clicks upward elevation, at 2750 fps that needs 6.5 clicks to be on at 500 yards, so a 1/4 MOA scope isn't precise enough. If your scope has repeatable 1/8 MOA adjustments that's 12 clicks vs. 13 in favor of the Swede, provided both rifles have exactly equal accuracy.

Caught a mistake. Make that 33 1/4 MOA clicks up to take zero range to 500 yards at a MV of 2750, 31 clicks at 2819 fps.

Sure as shootin' someone will resurrect this thread and berate me for that so I'm preempting the possibility.

6.5x55 will still be here long after the CM fades away

https://www.ballisticstudies.com/Knowledgebase/6.5x55.html

Do you own a T3 in 6.5X55?
If so please post your loads with 139gr. bullets and heavier..
That would be most helpful for the OP and myself since I recently acquired a T3 in 6.5X55 and would like to get the most out of it with modern powders like Rl-16 & 26..
Thanks

SIL in AZ now has my T3 Swede......

well the G/kids do.......

140 Nosler AB's.....H4831sc....

this load always worked purty good .......

Ha!
That'll do tikkanut..
I have all those components that you used in your load less the 140 NAB..
Have plenty of Hornady 140's, a couple boxes of Lupa 139's and 3 boxes of 140 NP..
Looking at the Hodgdon, manual your load should be running 2600-2650 fps @ around 45,700CUP..
Will start with Hodgdon data but hoping I can find your accuracy @ the next node up..
Thanks again..

tikkanut, what velocity is that AB running?

In the Tikka platform I prefer the 6.5X55 swede over the 6.5 Creedmoor due to mag restraints. You can load any bullet you want to in the 6.5X55 tikka and reach the lands but not so with the 6.5 Creedmoor unless you change the bolt stop and use an 06 length mag.

Another plus to the 6.5X55 swede is 100 pieces of Lapua brass is $80 vs $120 for 6.5 Creedmoor.

The 6.5X55 swede also has a longer neck that IMO help reduce throat erosion better than the 6.5 creedmoor.

In a hunting rifle setup especially the tikka I cannot find a single application where the 6.5X55 swede isn't a better fit unless one wasn't reloading there own.




Trystan

Do the M+ mags negate this?

Yes it would if you order the 06 length mag. I don't know if the M+ creedmoor mag is 06 length or not. You would still have to change the bolt stop.



Trystan

.

Yes. Lots of space to load for the lands. Pretty sure all 6.5CM T3s come setup with the M+ and proper bolt stop, but I'd confirm with Darrik before purchasing.