6.5x55 flavors

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mleeber

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Oct 13, 2004
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Morning All! I am looking at building a 6.5 on a remington 700 long action. I have narrowed it down to .260AI, 6.5PRC or 6.5x55 Improved and I am leaning towards the 6.5x55. My problem is that I am am seeing 6.5x55 Ackley Improved, 6.5x55 BJ AI (Bob Jourdan Ackley Improved) and regular 6.5x55 Improved. AmmoGuide is where I get my initial info and they only list the 6.5x55 Improved. It has a 54 degree shoulder which I like more than the 30 or 40 degree shoulder of the other two but I cannot find any other sources that list a 6.5x55 Improved with a 54 degree shoulder.

Anyone have any insight into the 6.5x55 confusion? I am thinking that 54 degree shoulder may give me a little more barrel life over the 30 or 40.

Thanks!
Mark
 
Morning All! I am looking at building a 6.5 on a remington 700 long action. I have narrowed it down to .260AI, 6.5PRC or 6.5x55 Improved and I am leaning towards the 6.5x55. My problem is that I am am seeing 6.5x55 Ackley Improved, 6.5x55 BJ AI (Bob Jourdan Ackley Improved) and regular 6.5x55 Improved. AmmoGuide is where I get my initial info and they only list the 6.5x55 Improved. It has a 54 degree shoulder which I like more than the 30 or 40 degree shoulder of the other two but I cannot find any other sources that list a 6.5x55 Improved with a 54 degree shoulder.

Anyone have any insight into the 6.5x55 confusion? I am thinking that 54 degree shoulder may give me a little more barrel life over the 30 or 40.

Thanks!
Mark

I am not a fan of the AI stuff, the claims for the cartridges are primarily hype. Take a look at the increase of powder and if it is in single digits you will not actually have much velocity increase over the parent cartridge. How Ackley and Ackleyites got their velocity increases was due to pressures increases 15,000 to 20,000 psia above the parent cartridges.

Shoulder angle will do nothing to increase barrel life. What matters is the pressure you are operating at and the amount of powder you burn in the tube. Back in the day, there were lots of unsubstantiated claims about shoulder angles, and they were all psuedo science.The higher the pressure and the more powder, the shorter the barrel life will be.

You want super high velocities, go for the 264 Win Mag. You will get about all the velocity you can get, and your barrel life will be around 700 rounds. One shooter I met, his 264 Win Mag key holed around 800 rounds. You push that 6.5 mm bullet in a smaller case your barrel life will be about 1400 rounds.

I think my velocities with a 20" barrel are just fine with the parent cartridge and is plenty accurate:

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The greatest increase in velocity came from shooting this cartridge in the 29" military barrel. Velocity was 200 fps faster with the same military ball ammunition in a 24" barrel. That is a real increase without having to pop primers.

Notice, same load, same barrel length, two different velocities. The world is not only queerer than we imagine, it is queerer than we can imagine.
 
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Nice work and the rifle looks like it just came out of the box. Provides hope for those of us who dont want to have a Proof barrel installed every season. Thanks!
 
@Slamfire that's some good shooting! Are those factory rifles?

All I did was to bed the actions. They shot horribly with the factory bedding and both rifles had factory pressure points in the fore ends. My experience with free floated barrels makes me wonder why anyone pressure beds the things. I never had a rifle shoot better with a bedded barrel.

I purchased this rifle from the original owner. Post WW2 he took a M1917 action, had a custom barrel installed, and did the stock work himself. He perfectly fit the barrel to the fore end. The contact had to be 100% between barrel and fore end, and that was the custom of the time. It shot horribly:

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I bedded the action and free floated barrel. The rifle went from flinging shots to making round groups. It is accurate enough to be a decent hunting rifle.

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The 6.5 Swede targets I posted happen to be the best groups I shot with the rifles. So I am deliberately providing misleading information. The rifles and myself don't always shoot like that. Still, I think those groups are really good for lightweight hunting rifles with factory barrels.

It was interesting to see how the barrels reacted with identical ammunition. Both tubes loved 140 SMK's, the Remington did well with 140 grain Rem Core Lokt,

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But the Winchester barrel sure hated them

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That Devcon bedding sure is magical. I'm always impressed by people who can shoot well from unsupported firing positions.
 
mlleeber,
Slamfire is correct, that shoulder angle has nothing to do with throat wear. That old TP angle thing... I never bought into it. You burn a lot of powder at high velocities you will burn the throat out period. Believe me.... I own and have shot 1000's of rounds out of a 6.5-300 WWH (a 6.5-300 Weatherby) and a 6.5-300 Win Mag. The Win Mag used the original short neck of the 30 caliber case and the reamer ws ground to simply neck down to 6.5 with original neck angle. The WWH had the Weatherby shoulder on it but a more than 1.2 caliber to neck length ratio. Both cases with burn a throat in no time and around the same round count.

But I can also speak directly with experience with a 6.5x55 Ackley Improved. My chamber and reamer were cut to a true Ackley improved specs. Meaning 40 degree shoulder leaving the original neck to shoulder junction in place and .008"/in of body taper for the case body. I didn't have these rifles built for speed. I had this built right when the 6.5-284 first made waves and the original winchester brass ran out and the new Lapua stuff had not been imported yet. So I built my rifles to duplicate 6.5x284 ballistics without having to deal with questionable brass. I could already get RWS, Lapua, nd Norma brass in 6.5x55 and not really on 1 importer for the 6.5-284 stuff.
I have had (5) 6.5x55 AI barrels chambered for 2 different rifles. All barrel are 28-29" long. My accuracy loads I could cruise at 2940fps all day long for long range work. I did test once to go up to see what this ackley chambering would actually go to and I did clock some rounds right at the 3100 fps mark using various 140gr bullets. But you wouldn't have good case life shooting those 3100 fps loads. They were safe in my rifles, but they were up there. At 2940fps using 50+gr of H4831 I have 15-20 firing on many cases and they are still going. I used all Lapua and RWS brass. I did have 1 batch of 60 Norma cases but the primer pockets did open up on them and some of those were retired before 10 loadings if memory serves me correctly.

You will not gain much more if anything with a 54 degree shoulder.

Slamfire,
Nice rifles! And I 100% agree with your thoughts on bedding actions and floating barrels. No pressure points. If nothing is touching the barrel, then the only influence on the harmonics is the load itself and the metalurgy/machining of the barrel itself. Assuming a good bed job of the action. Much more predictable than relying on a pressure point or bedding the whole barrel channel. And nice shooting with those old girls at 300yds.

Be Safe,
Steve
 
Not to add to your confusion, but look up Lapua 6,5 Skan data. This is the unaltered 6,5x55 loaded to modern pressures (as in your m700 action) and see if that fits your design parameters without the extra fiddling with brass forming (which also wears on barrels)
 
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