# Muzzle velocity and barrel length



## SLCHunter (Dec 19, 2013)

Gentlemen: I've made the jump and started reloading. Lots of fun, with first good results. Question is the following: 

I have three recipes, all with different max powder charges. 
1) 60.5gr (24"barrel)
2) 57.5 (26")
3) 62 (24") 

Corresponding velocity is 3000fps. I have a 22" barrel, no pressure signs and average velocity at 2940fps with a sub-MOA group at 60.2gr. 

60.5 and 60.8 produced comparable, but not quite as good groups, and velocity crept up to 2980. 

Given my shorter-than-recipe barrel, should I make 60.2gr/2940fps the point to fine-tune around? Meaning, is it correct that a shorter barrel will cost fps-per-inch? I think I've read that somewhere, but can't recall -- any suggestions would be much appreciated. 

I have no interest in pushing the envelope in terms of pressure.


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## LostLouisianian (Oct 11, 2010)

SLCHunter said:


> Gentlemen: I've made the jump and started reloading. Lots of fun, with first good results. Question is the following:
> 
> I have three recipes, all with different max powder charges.
> 1) 60.5gr (24"barrel)
> ...


Whole lot of info missing. Caliber? Gun? Powder? Projectile?


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## derekp1999 (Nov 17, 2011)

If you are happy with the results at 60.2gr, then I would say go with it! Sounds like a load I'd be happy with, good work.

Make your seating depth tweaks and such and see if you can get it to where you like it more.


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## DallanC (Jan 13, 2009)

Yes a shorter barrel is slower than a longer one, generally. Twist can also affect velocity as can the surface of the bore and other factors.

I cant find it right now, but there was a article where a barrel builder took a single barrel with a known load, and started cutting 1" off the end and recording the velocity differences. I remember it falling within the widely accepted 25-50fps per inch figure talked about often.


-DallanC


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## DallanC (Jan 13, 2009)

Here is some info on it from Chuck Hawks:



> The 45th Edition of the _Lyman Reloading Handbook_ also has a table showing Center Fire Rifle Velocity Vs. Barrel Length. Their figures apply to barrels between 20 and 26 inches in length and agree with the Remington figures. The Lyman table shows the following approximate velocity changes:
> 
> 
> For rifles with muzzle velocities in the 1000-2000 fps range, the change in velocity for each 1" change in barrel length is 5 fps.
> ...


So caliber matters as well as to the velocity loss with shorter barrels.

-DallanC


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## massmanute (Apr 23, 2012)

There is an interesting website

http://www.ballisticsbytheinch.com/calibers.html

It mostly deals with pistol rounds, in various barrel lengths, including rifle-length barrels.


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## DallanC (Jan 13, 2009)

Here's one article on a barrel cut down and measured.

http://www.thetruthaboutguns.com/20...t-barrel-length-muzzle-velocity-and-accuracy/

-DallanC


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## DallanC (Jan 13, 2009)

Here ya go, this was what I read. If you need more info post you are on your own lol...

http://honors.usf.edu/documents/thesis/u82488180.pdf

-DallanC


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## SLCHunter (Dec 19, 2013)

LostLouisianian said:


> Whole lot of info missing. Caliber? Gun? Powder? Projectile?


Tikka T3 30-06 22" barrel 11 twist 
Boyds laminate stock pillar/glass bedded 
H4350 CCI primer Berger 155.5gr Hybrid


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## SLCHunter (Dec 19, 2013)

DallanC said:


> Here ya go, this was what I read. If you need more info post you are on your own lol...
> 
> http://honors.usf.edu/documents/thesis/u82488180.pdf
> 
> -DallanC


Ha! Thanks for all this info, I'll read some and will come back with results. 
Attached is my best group, with 60.2gr of Hodgdon 4350, btw...


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## waspocrew (Nov 26, 2011)

SLCHunter said:


> Ha! Thanks for all this info, I'll read some and will come back with results.
> Attached is my best group, with 60.2gr of Hodgdon 4350, btw...


Typical boring accuracy from a T3 :grin:


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## SLCHunter (Dec 19, 2013)

waspocrew said:


> Typical boring accuracy from a T3 :grin:


I got a new powder scale (beam), instead of the terrible Hornady digital entry level ... so I hope I can improve on it ;-)


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## LostLouisianian (Oct 11, 2010)

SLCHunter said:


> Tikka T3 30-06 22" barrel 11 twist
> Boyds laminate stock pillar/glass bedded
> H4350 CCI primer Berger 155.5gr Hybrid


Have you tried the 175 gr Bergers? I haven't reloaded a lot yet for my .30-06 but am looking into the heavier bullets for it. I know the 175 gr Bergers are recommended as replacements for the highly accurate 7.5x55 rounds used in my Swiss K31's.


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## SLCHunter (Dec 19, 2013)

LostLouisianian said:


> Have you tried the 175 gr Bergers? I haven't reloaded a lot yet for my .30-06 but am looking into the heavier bullets for it. I know the 175 gr Bergers are recommended as replacements for the highly accurate 7.5x55 rounds used in my Swiss K31's.


No haven't! This is the first bullet I'm trying ... I'd probably go with a Nosler Accubond 165 if this one doesn't pan out before I go to 175.


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## derekp1999 (Nov 17, 2011)

My Remington 700 likes the 180gr over the 150gr & 165gr... it might be worth investigating the heavier/longer bullet.


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## swbuckmaster (Sep 14, 2007)

LostLouisianian said:


> Have you tried the 175 gr Bergers? I haven't reloaded a lot yet for my .30-06 but am looking into the heavier bullets for it. I know the 175 gr Bergers are recommended as replacements for the highly accurate 7.5x55 rounds used in my Swiss K31's.


I wouldn't look at the BC of a particular bullet and think it will work in any gun without looking at what the bullet manufacture reccomend on twist rate of the rifle. I dont think 1/11 will stabalize the 175's.


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## SLCHunter (Dec 19, 2013)

swbuckmaster said:


> I wouldn't look at the BC of a particular bullet and think it will work in any gun without looking at what the bullet manufacture reccomend on twist rate of the rifle. I dont think 1/11 will stabalize the 175's.


Berger (http://www.bergerbullets.com/products/hunting-bullets/) says that only the 210gr 30 cal bullet requires 11 twist, all smaller bullets can do with slower twist ...

What reasons would there be to expect a heavier bullet to be more accurate? I like the velocity and hence flat(ter) trajectory of the 155gr.


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## swbuckmaster (Sep 14, 2007)

The 210 grain bullet matches the rifle twist. It also has a better bc. BC is all about slipping the wind long range. Do you want a perfect spiral when throwing a football? Yes and you want your bullets to stabalize as well. Matching reccomended twist rate gets you close.

If you dont care to shoot past 400 yards it probably doesn't matter with half inch groups like the op is getting with one of his loads.

Heavier bullets also retain their energy and speed longer. you can also match any buller to turret so verticle drop is one of the last things I'd look at unless you don't care to shoot past 400 yards


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## waspocrew (Nov 26, 2011)

SLCHunter said:


> Berger (http://www.bergerbullets.com/products/hunting-bullets/) says that only the 210gr 30 cal bullet requires 11 twist, all smaller bullets can do with slower twist ...
> 
> What reasons would there be to expect a heavier bullet to be more accurate? I like the velocity and hence flat(ter) trajectory of the 155gr.


It all just depends on your intended use for your rifle - If you're planning on shooting long range with it, I'd try to go with the heaviest bullets your twist rate will stabilize.

If you're just looking for a great deer load, anything from 150's to the 180's are fine. I really don't think you need a 210 to take a deer down with. Plus, the T3 magazine limits how far out you can seat those long heavies.

Those groups look great as they are. I'd try tweaking the seating depth to see if that helps tighten it up even more.


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## 35whelen (Jul 3, 2012)

great table dallanc. i was curious how much velocity i would lose from my 16 1/2" .338 federal ruger frontier


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## SLCHunter (Dec 19, 2013)

swbuckmaster said:


> The 210 grain bullet matches the rifle twist. It also has a better bc. BC is all about slipping the wind long range. Do you want a perfect spiral when throwing a football? Yes and you want your bullets to stabalize as well. Matching reccomended twist rate gets you close.
> 
> If you dont care to shoot past 400 yards it probably doesn't matter with half inch groups like the op is getting with one of his loads.
> 
> Heavier bullets also retain their energy and speed longer. you can also match any buller to turret so verticle drop is one of the last things I'd look at unless you don't care to shoot past 400 yards


Ok. I had not heard of the recommendation to match twist to bullet -- thought that this is only the minimum required to stabilize?!

And: I guess the discussion on what grain bullet you need to take a big game animal can go on forever ... ;-)


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## swbuckmaster (Sep 14, 2007)

Yup with a 30 caliber you don't need to worry not having enough gun.


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## Bob L. (Jan 11, 2015)

Wouldn't worry to much about bc until past 500 yards. Looks like it shoots go kill stuff with that load you have.
I would think in an '06 those would be more enjoyable to shoot than the 210's.
I never hear anything bad about those Tikkas.


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## SLCHunter (Dec 19, 2013)

Bob L. said:


> Wouldn't worry to much about bc until past 500 yards. Looks like it shoots go kill stuff with that load you have.
> I would think in an '06 those would be more enjoyable to shoot than the 210's.
> I never hear anything bad about those Tikkas.


.... once you replace the horrid stock!!


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## SLCHunter (Dec 19, 2013)

Finally got out to the range again ... (it's been a far too busy summer!) 
Attached is the best group with the load that I settled on, 60.1 of H4350. 

I shot as well some 1 moa groups; difference to this best 4 shot group is CBTO -- even though I don't load near the lands. It might just be my shooting?! That'd be my guess.


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