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  #1  
Old 11-25-2017, 03:27 PM
moorepower moorepower is offline
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Default 6X45 barrel

How long would a 6X45 barrel need to be for top or near top velocities. i am thinking of 55-75 grain bullets max.
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  #2  
Old 11-25-2017, 06:20 PM
squirrel_slayer squirrel_slayer is offline
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I'm going to be doing my 6x45 improved at 26-28" long personally but it's going to be setup more for 105gr bullets and a cheap long range trainer.

I played around with quickload and I want to say velocity started tapering off around 20"

one thing to consider which makes a huge difference in velocity is the freebore. a standard 6x45 which is setup for an AR (2.25" COAL) can benefit greatly with a longer freebore so more of the bullet is out of the case thus freeing up useable powder capacity.

if you know what bullet you plan to run many smiths (or reamer makers) can setup the rifle as to maximize this. you just load up a few dummy rounds with the bullets seated to where the base of the bullet (or bearing surface) is flush with the base of the neck.

one byproduct of this, is you do lose the ability to chase the lands once the throat errodes to far. but this can easily be fixed by running a heavier bullet or you can leave the shank of the barrel longer to allow for a setback in the future.
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  #3  
Old 11-26-2017, 12:56 AM
GrocMax GrocMax is offline
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Gonna need 26"-28" for top velocity, figure 20-25FPS less for each inch under 26 till about 16" then it falls off quicker. I find the WP 6x45 book data to be correct for my rifles.

Buddy has a suppressed 10.5" AR SAAMI 6x45 shoots Sierra 60HP varminter 2850 and 90g gameking 2350 with AA2200 and max loads (AR mag length).

My 6TCU with a 27" 8 tw will push a 70 Varmageddon to 3300, 3150+ fireforming. 58vmax 3600+ with ease.

None of these are optimal on the AR mag length restriction of 2.26"ish.

Last edited by GrocMax; 11-26-2017 at 01:06 AM.
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  #4  
Old 11-26-2017, 10:26 AM
kenbro kenbro is offline
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Hi squirrel slayer,
Do you think you will be able to get 1750 ft lbs and 2450fps with 100 grain bullets out of your 6x45 improved?
Very interested as that’s the minimum legal requirement for deer in Scotland.
I’ve been trying to achieve those figure with my 25-45, without success.
Getting 3000+fps with 90 grain GameKings
I would prefere the 6mm version, if i could get better performance.
Regards,Ken.
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  #5  
Old 11-26-2017, 11:41 AM
rickiesrevenge rickiesrevenge is offline
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Quote:
Originally Posted by kenbro View Post
Hi squirrel slayer,
Do you think you will be able to get 1750 ft lbs and 2450fps with 100 grain bullets out of your 6x45 improved?
Very interested as that’s the minimum legal requirement for deer in Scotland.
I’ve been trying to achieve those figure with my 25-45, without success.
Getting 3000+fps with 90 grain GameKings
I would prefere the 6mm version, if i could get better performance.
Regards,Ken.
Looking at quickload and hodgdon's data it should be no problem getting 2450fps with a 100gr bullet. Most of the data shows a top end of 2600+/-. Looking at a energy calculator you're gonna be short on energy though. Need 2810fps with a 100gr bullet to get there.

Aaron
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  #6  
Old 11-26-2017, 03:57 PM
kenbro kenbro is offline
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rickiesrevenge,
I should have stated... Minimum .24 cal; 100 grain minimum bullet, 1750 ft lbs and 2450 minimum velocity.
That sorta changes thing a bit.
Thanks,Ken.
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  #7  
Old 11-26-2017, 04:49 PM
william t. oviatt william t. oviatt is offline
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Ken
I know I have asked this before, but how do you "prove" the rifle/cartridge performance to those specs?
I am pretty sure they can be met with a 6TCU with a 100 grain min. bullet and the velocity seems easy too, out of a 22" + barrel!
I know I sure love my CZ 6TCU...I will do some chrono on my loads and let you know!!!
Do you have a favorite 6mm 100 gr. bullet you would like to see info on?

Bill
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Last edited by william t. oviatt; 11-26-2017 at 04:52 PM.
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  #8  
Old 11-26-2017, 06:43 PM
kenbro kenbro is offline
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Hi Bill,
Answer to first question is...no need to, unless, when out hunting there was a serious incident where the authorities might become involved!
For me it’s just personal satisfaction.

With both bullet weight and velocity being minimum specs, a 100 grain bullet would need to be going at 2800+ fps to reach 1750 ft lbs.

100 grain bullets I’ve been trying with in 25-45 are Sierra 1620.
Thanks, Ken.
Ps. Thinking of rebarreling the 1885 to 6x45I.
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  #9  
Old 11-26-2017, 08:14 PM
squirrel_slayer squirrel_slayer is offline
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Quote:
Originally Posted by kenbro View Post
Hi squirrel slayer,
Do you think you will be able to get 1750 ft lbs and 2450fps with 100 grain bullets out of your 6x45 improved?
Very interested as that’s the minimum legal requirement for deer in Scotland.
I’ve been trying to achieve those figure with my 25-45, without success.
Getting 3000+fps with 90 grain GameKings
I would prefere the 6mm version, if i could get better performance.
Regards,Ken.
seems most have already answered this but i'll give my info. with cartridge lengths in the 2.5-2.6" range with bullets like the 90gr swift scirocco, and 95/100gr nosler partitions velocities in the 2700-2800ft/sec range should be possible from a 22" barrel with 8208xbr

one bullet that I haven't heard any reports back on yet that interests me is the newish 103 eld-x by hornady. this bullet at even at 2600 ft/sec should really give a great advantage in the wind and pulls away from the pack around 100 yards in the energy department still carrying 1000+ft/lbs at 300 yards

for all intensive purposes the TCU and cartridge I plan to try is very similar with the major difference being the 30' shoulder vs 40' and the rest is mostly in the throating.

I feel going with a 8 twist barrel is also the big divider. having the ability to use high bc bullets is what allows the dimunitive catridge come into it's own. if you cant generate the velocity then it's best to keep what you can get as long as you can.

I have also read that running lighter bullets with alot of RPM can also increase terminal performance on varmint sized game assuming it doesn't come apart from the centrifugal force during flight.

Last edited by squirrel_slayer; 11-26-2017 at 08:33 PM.
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  #10  
Old 11-27-2017, 05:24 AM
Johnly Johnly is offline
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I have a 20" 1/7 twist 6x45 AR-15 and the top velocity loads in my rifle are:

107 Sierra MK 30.0 2000MR RP-7 1/2 LC 07 2484fps 2.575"
107 Norma Moly 30.0 Leverloution RP-7 1/2 LC 07 2471fps 2.575"
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