6.5X55 vs .260 remington reloading data

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pacobillie

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I reload for 6.5X55 Swedish. Given that the .260 Remington has nearly identical ballistics, uses the same bullets, and has nearly identical powder capacity in the case, and a similar cartridge shape, it begs the question as to whether one can use the .260 reloading data for the Swedish cartridge, provided that one respects the maximum chamber pressure, or does the slightly different cartridge shape render the data invalid for the 6.5X55?
 
Not quite sure why you would want to do that.
260 data has been developed for modern, strong actioned rifles ONLY.
6.5/55 data presumes use in older M94/96/38 swedes, and krags. To a lower pressure.
If you were to chamber a M98 or M700 etc. in 6.5/55 then you could load it up to 260 pressure specs. safely.
However:
If you are loading a 260 built on a swede/krag action, the pressure limits of that action must be respected. I would not suggest firing 260 factory loads.
 
vviking said:
Not quite sure why you would want to do that.
260 data has been developed for modern, strong actioned rifles ONLY.
6.5/55 data presumes use in older M94/96/38 swedes, and krags. To a lower pressure.
If you were to chamber a M98 or M700 etc. in 6.5/55 then you could load it up to 260 pressure specs. safely.
However:
If you are loading a 260 built on a swede/krag action, the pressure limits of that action must be respected. I would not suggest firing 260 factory loads.
Click to expand...

There is more data available for the .260 BWOE,Hoggdon lists BLC-2 loads for the .260, but not for the 6.5X55

I would respect the Swedish cartridge maximum allowable pressure. The question is whether a load that produces 46,000 CUP or the PSI equivalent in .260 will produce a nearly identical pressure in a 6.5X55
 
Paco,
Perhaps I was a bit off to the side of your point of aim. Better safe etc..
If you put the same charge into a larger capacity case, pressure goes down.
To be sure, you would need to measure both case's capacity in grains of water and adjust start loads accordingly.
The problem I see with unpublished data used in a 46000 cup cartridge is how to read the pressures at all. Case head expansion and primer appearance dont do much.
If it was me, I'd start low with 7x57mm BLC2 data, and/or the next fastest powder(varget?) and work up slowly.

Hodgdon's 2004 annual:
6.5x55, 24",
107gr. sie hpbt
3.050"oal
bl-c(2)
start 41gr. 2784fps 37,300cup
max 44.5gr. 3050fps 45,600cup
 
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Reasons why you can't interchange data here: These cartridges are loaded to different max pressure standards. One of them might be used in 115 year old rifles, and the other in rifles less than 20 years old. Last but not least they have different powder capacity.

Generally speaking you should be able to run the light .260 published data in a 6.5x55 without incident because the 6.5 is a larger case and pressure should go down. But there is no real advantage to doing that unless you want bottom end loads.

If you are an experienced reloader it's not hard to work up a load with a powder, but don't go too far if you're not sure what you're looking for.
 
Guys:

Thanks. Between all of your answers, I did find what I was looking for.

My goal was to find a starting point to develop a load, if there is no published data. Just to illustrate: let us say that I want to use BL-C(2) and a Nosler 140 Gr. Partition in the 6.5X55. For the .260, the published loads are as follows:


140 GR. NOS PART Hodgdon BL-C(2)
Min: 34.0 Gr. 2412 FPS 52,800 PSI
Max: 36.6 Gr. 2557 FPS 59,000 PSI

Knowing that for the Swede (other than the M94 and the Krag), the MAP is 55,000 PSI, and that it has a slightly larger case than the .260, the resulting pressures should be a tad lower. So, if I stay with a load that would yield a pressure of less than 55,000 PSI in the .260, it should yield a slightly lower pressure in the Swede, and thus be safe.

Of course, I would start with a lesser load and work my way up to MAP.
 
I would say the case capacity of 6.5x55 is more than a tad bigger than the 260Rem. I have a 260 Rem Ackley - it is about the same capacity as Swede.

Water capacity

260 Rem 54.8 gr.

260 Ackley 56.5 gr

Swede 57.3 gr
 
I've always gotten better results using slower powders in the 6.5x55. H4831, IMR4350, and IMR4831 have all been very good. Do you have a chronograph? i'd be interested to see your results using BLC-2.
 
pacobillie said:
Guys:

Thanks. Between all of your answers, I did find what I was looking for.

My goal was to find a starting point to develop a load, if there is no published data. Just to illustrate: let us say that I want to use BL-C(2) and a Nosler 140 Gr. Partition in the 6.5X55. For the .260, the published loads are as follows:


140 GR. NOS PART Hodgdon
Min: 34.0 Gr. 2412 FPS 52,800 PSI
Max: 36.6 Gr. 2557 FPS 59,000 PSI

Knowing that for the Swede (other than the M94 and the Krag), the MAP is 55,000 PSI, and that it has a slightly larger case than the .260, the resulting pressures should be a tad lower. So, if I stay with a load that would yield a pressure of less than 55,000 PSI in the .260, it should yield a slightly lower pressure in the Swede, and thus be safe.

Of course, I would start with a lesser load and work my way up to MAP.
Click to expand...

Nice to see a thinking person who does not blindly cling to load manuals - the "If it's not in there, don't use it!" types.

Your logic is sound - in the absence of load data, find a cartridge with the same bore diameter, but similar case capacity, and if it's smaller, the resulting pressures will be lower, and if larger, they will be higher. Of course OAL is another variable to consider.

I use 260 Rem "+" data for my 6.5X55 (in a M98), and when I can find 260 AI data, I use that. Yes, most North American load data is geared towards the older military stuff floating around and they are limited to about 45K psi, but there are many M98's and other modern actions out there that can comfortably work at 260 Rem pressures. The action is the limiting factor, not the brass, like some will claim, so 6.5X55 can be loaded past 45K with the right action.

Have fun with BL-C(2), but at the end of the day, you'll do better with something slower like H4350, H4831, or Re22.
 
Good to know that my logic is sound. BTW, BL-C(2) was given out as an example only, because it is a spherical powder, which makes measuring easier.

I currently load 49.6 grains of VV N560 behind a Hornady SST 129 Grains and am getting good accuracy and no signs of over-pressure in a Mauser 96 dating back to 1909 or 1919 (the third digit is where the receiver has been drilled and tapped). That load is just a tad below the stated maximum load for a 130 grain bullet per the VV reloading manual. According to VV data, the speed should be around 2850 FPS, although I do not have a chronograph to confirm that. I also believe that the VV manual gives out the "European loads" as opposed to the milder "North American loads". My only qualms about the N560 are that it is expensive, and most importantly, it is hard to measure consistently with a volume measure. Hence my interest for spherical powders.

BTW, I believe the MAP for North American loads is 46,000 CUP or 51,000 PSI.

AFAIK, the European numbers are 51,000 CUP and 55,000 PSI.
 
I put 6,000 rounds though a Shilen 6.5x55 barrel (30") on a Savage action. used the Sierra 142 match bullet and an almost full case of RL22. Velocity was 2950.

Barrel was replaced with a 30" 260 Ackley. case capacity is about the same. Get good results with 4831SC, 4350 for case forming, and RL22.

6.5x55

48 RL25
45 RL22

260Rem AI

48 4831SC
45 4350
50 RL22

These are all accuracy loads for my rifle. Custom reamer throated deep. Not suitable for old military actions.
 
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