How to match powder to barrel length?

[BillLarson]

Do your homework.Read all the load recommendations (online) from different powder companies.Buy a couple reloading manuals.Pick up the free manuals from powder companies at gun stores.
Every gun is different,every bullet is different every primer is different and every powder is different.Buy powder 1 pound at a time.... when you find your combo...get an 8# jug of it....
Start low on powder charge and work up..... do a ladder test...

 

[Philward]

QuietTexan well covered a lot, and then there is the counter consideration; why go with a shorter barrel?

Shorter barrels are more forgiving to barrel tune because they're stiffer for weight.
Desiring this attribute while adding barrel length, also means moving up in profile weight to keep stiffness.
This changes gun balance and could force you to add weight to the butt stock to regain good balance.

A good LR big boomer is likely heavy, and for stalking hunting, less field practical.
So then you're considering fluting or carbon barrel enhancements.
It always begins with a bullet, then cartridge to push it, then barrel to cover, and overall system to reach all needs.

So... Benefits of the longer barrel are pointability? More time in contact with the bullet to guide it more precisely? If that 28" barrel were 1.375" diameter at the muzzle it would be real easy to tune, similar to an 18" barrel that is 0.75" at the muzzle?

 

[lyle2231]

Gordons Reloading Tool is another option. And it's free!

I just tried it. It's a little hard to understand IT wise. The gentleman Gordon passed in January. His wife lists 2048 as the unsupport date. Still trying to make it work with iOS.
But it is a good suggestion.

 

[Mikecr]

So... Benefits of the longer barrel are pointability? More time in contact with the bullet to guide it more precisely? If that 28" barrel were 1.375" diameter at the muzzle it would be real easy to tune, similar to an 18" barrel that is 0.75" at the muzzle?

No, a stiffer barrel whips around less distance at the muzzle. It's more forgiving in that a mis-timed load can still shoot 'ok'.
But that's barrel tune. Powder tune can favor a longer barrel, depending on the cartridge & load.
It's all a big balance, so it's in our best interests to steer clear of extremes, as they're harder to get in good balance (for hunting).

 

[milboltnut]

longer barrel length will produce higher velocity. Choose a powder with the highest velocity and go from there.

 

[hydehunter]

You're comparing the listed data for a 308 to your results from a 30-06?

What are the velocities when you shoot the same loads in the 18" barrel compared to the 24" barrel?

no, listed 308 loads from the book only, on my 30.06 I only used H4350 when it had the 24" barrel on it. after it was cut to 18 I looked for a faster burning powder and was able to find the IMR8208 and worked up a load with it. I figured H4350 would be to slow of a powder and was concerned about a bunch of smoke coming out the suppressor

 

[Seabeeken]

I'm not a believer of the "faster powder for short barrels" -- I've tried it and in my experience it does nothing.

I believe the burn rate is based off the cartridge and bullet weight.

I have a 16" 308w and a 26" ( also same in 6.8spc and 223/5.56)--- in the 16" I tried a multitude of "faster" powders and could never get faster speeds for the same weight bullet. The faster burn rate powders just show pressure signs earlier in my experience.
Faster powders for lighter bullets- yes, that works for me.

Others may have different results but faster powders for shorter barrels don't work for me

In shorter barrels, slow powders are a waste since a good portion is blown out the barrel as a fireball not to mention that slow powders moving down the barrel are erosive and increase the length of firecracking. Ive had good results with powder burns in the 96-100% range. TETO

 

[Mikecr]

Or, fastest powder providing 100% load density at SAAMI max pressure, AND reasonable muzzle pressure, with chosen bullet and barrel length.
Then muzzle velocity ends up a product of the plan (like designed capacity).

 

[GrayCreed]

Magazine length plays an important part in how slow of a powder you can use.

Also I'd look at the science of why certain bullets like certain powders more or less.

I think this may(I'm still learning too) have more to due with the barrel TIME and barrel NOTE than going from H4350 to 4831. That said H4350 is going to work alot better with 120-130g and you may be able to stuff the case full of H4831ssc or 7828sc without seeing pressure behind a 147, 150, or 156g bullet. Your main problem is going to be getting enough in the case. That's why I all but gave up to n trying to load Re23 behind the 150smk for my shillen barrel (26")
I'll probably try it again but the crunchy loads just don't shoot good.
As far as going slower maybe look at the slower side of the 4350 burn chart without jumping straight to the 4831 chart.

 

[johnthemc]

I'm interested in learning the theory around matching a bullet/powder combination to a new barrel. There are some threads with people suggesting different powders to try, but that's not what I'm looking for; instead, I'd like to understand the science or art behind thoughtfully, from data, choosing a powder that best fits the bullet/barrel combination.

I've been shooting a Savage 10 in 6.5 CM, 24" bbl, 1:8 twist, with 140gr, H4350, and I'm moving to a 28" Shilen bbl, 1:8 twist. Conventional wisdom says to start load development again and work up to pressure signs, but it occurs to me that it may be short-sighted to assume that H4350 will be equally effective in a longer barrel. Is it true that there are powders with a better burn rate for a given barrel length? And yes, also matched to a bullet weight?

So, my specific question is, how do experienced reloaders think about different powers on the burn rate chart, as it relates to barrel length? Is it generally true that shorter barrels require a faster powder, and longer barrels a slower one? And if so, then theoretically, moving from a 24" to a 28" bbl might drive a consideration of a slightly slower powder? I know this isn't a large change in barrel length, compared to moving from a 16" to a 28", but still, it's the theory behind all this that I'd like to understand. Again, I'm not looking for powder suggestions, but I'm very interested in how knowledgeable reloaders think about burn rates related to barrel length. thx

This is something I need to learn.

 

[WildRose]

That's not really how it works, But I'd build it at least 24" if it were mine. Speed will be determined by your load and chamber/throat. Longer tubes are more efficient, giving you the 3k u want with less inputs, but you gotta haul the fence post around too so the compromise is needed.

Considering the 6.5L is designed and optimized for 16-20" barrels that doesn't make a lot of sense to me.

You're only using 38-40gr plus/minus and fast burning powders like H4350, RL16, or varget so how much velocity would you gain with a 24" bbl over 16-20"?

What am I missing here?

 

[WildRose]

Magazine length plays an important part in how slow of a powder you can use.

Also I'd look at the science of why certain bullets like certain powders more or less.

I think this may(I'm still learning too) have more to due with the barrel TIME and barrel NOTE than going from H4350 to 4831. That said H4350 is going to work alot better with 120-130g and you may be able to stuff the case full of H4831ssc or 7828sc without seeing pressure behind a 147, 150, or 156g bullet. Your main problem is going to be getting enough in the case. That's why I all but gave up to n trying to load Re23 behind the 150smk for my shillen barrel (26")
I'll probably try it again but the crunchy loads just don't shoot good.
As far as going slower maybe look at the slower side of the 4350 burn chart without jumping straight to the 4831 chart.

Funny I know a lot of guys that swear by some heavily compressed loads but I'm not one of them. It just makes me nervous putting an explosive under that much pressure and I'm like you, I've never shot any compressed loads that impressed me for accuracy at least in my rifles.

I've also then had problems with bullets wanting to walk out over time with compressed loads if I didn't crimp them.

 

[Veteran]

Yes neck tension is a must w compressed loads. I wont go more than about 103% case fill on any load even if its safe pressure wise.

Just not worth the trouble it takes mechanically to not make a mess
and still get the seating calibrated and stay that way.

Especially w big chunky stick powders....not worth it.

 

[WildRose]

Yes neck tension is a must w compressed loads. I wont go more than about 103% case fill on any load even if its safe pressure wise.

Just not worth the trouble it takes mechanically to not make a mess
and still get the seating calibrated and stay that way.

Especially w big chunky stick powders....not worth it.

I've ceased doing so completely and the results show it was a smart move.