Re: 221 & 17 fireball reloading questions.

[bobcat93]

Happy 4th of July gentleman.
I've been reloading for about 23-25 years now, i'm just now starting to see and understand powder burn rate in relationship with case capacity.
Honestly I never thought about it much when buying propellant. I would look at 3-5 reloading manuals, see what is working best , and go buy 2-3 different propellants, then start working.
It is a very expensive, and naive way to find what works best in my firearms.
Then there is the reloading voodoo, ( just because the manual says its great, doesn't mean squat)
Now ..I've been reading alot on line to narrow down my choice in propellants for the 221 fireball, and the 17 fireball cartridges.
My question is :
Obviously one cartridge is a .17 cal. And the other a .22 cal. Yet both use the same case.
Can some one tell me how changing calibers while using the same case would create a need to changes propellants when reloading for these chambering.
I'm trying to learn how to more effectively find suitable propellants based on burn rate and case capacity. ( what should be used) and why.
I would like to think I'm reaching a new level in my reloading knowledge, and skill..
Thank you.

 

[bheadboy]

I guess the best way for me to answer is the following - as the case shoulder/neck is reduced to create the 17 (also 30-06/280/270/6.5-06/25.06/6.06 etc.)

the pressure of the burning powder must find a way to escape - down the bbl is the only way - however the exhaust pipe is smaller thus the way out is smaller thus the resistance is greater thus pressure release is slower - so you will find the pressure either high longer or spike higher as the powder continues to burn and build pressure (burn rate).

thus power gr weights and burn rates are key to controlling the pressure within each case design --- and a big consideration is the bullet weight ( lighter vs heavier) of the two cases - also the throat length and twist rate to a somewhat lesser degree. obviously the 17 vs the 221 the bullet weights are different.

just my understanding - hope this helps you

Bob

 

[bobcat93]

Thank you for the reply.
With all this in mind, what are the key factors to look at what choosing a propellant. I assume velocity= pressure . so a propellant could be chosen in relationship between twist rate and barrel length , burn rate ..witch is all limited by pressure.
The whole thing that got me started on this was when I was shooting my Thompson center contender (221 fireball) with a 10" barrel there seem to be a propellant grains left all the way down the barrel. Then I thought perhaps I need a faster propellant, then I started thinking about the parent case the 222 rem.
With less case capacity , higher pressure, and a short barrel how does one choose what is the best propellant to make this work harmoniously

 

[bheadboy]

you are describing a number of things here, bbl length and powder left is a double edge

the powder left in the bbl or muzzle blast is an indication the powder is too slow for the combination of case, bullet, bbl length you have,

so a slightly faster powder with adjusted gr weight is in order. check the loading powder burn rate charts on Hodgden's page and then check their recommended loads for your combination. other data is available in Lyman, Sierra, etc. loading manuals.

this is where load work up is a major factor of testing out the suggested powder/loads/bullet combo you see in these publications

don't get overly worked up over twist/throat at this point.

bob

 

[Dave Berg]

I'm trying to learn how to more effectively find suitable propellants based on burn rate and case capacity. ( what should be used) and why.

I strongly recommend that you buy a copy of QuickLoad and spend the time to learn to use it properly. It can be a real eye-opener.

With less case capacity , higher pressure, and a short barrel how does one choose what is the best propellant to make this work harmoniously

Same answer. QuickLoad. Best money I ever spent other than the $10 for a marriage license.

 

[Outrider27]

In addition to the good advice above, don't get too tied up in a technical approach to finding the right powder for a specific caliber to the exclusion of potential good performers that aren't so obvious. I had a load for a 14" bull barreled 30-30 Contender that left powder in the barrel and made quite a muzzle flash. The load used H380 and you wouldn't find that powder listed for the 30-30 WCF much of anywhere outside of a few specialty pubs catering to IHMSA metallic silhouette and other long range pistol fanatics. Was it too slow? Yup. Did it drive nails out to 200 meters - you better believe it. Nothing wrong with trying to achieve technical perfection, but also keep in mind that your firearm will tell you what it likes, and if it likes something offbeat and maybe not as efficient, don't be afraid to go with the flow. Even if your line mates sometimes laugh and accuse you of trying to start grass fires at the range on dry days when you crack off a string... :

 

[bobcat93]

Thank you gents,
It's good to hear all the different opinions. I guess that is the voodoo of reloading..you just never know what your gun will like best.

 

[MrMajestic]

I'm trying to learn how to more effectively find suitable propellants based on burn rate and case capacity. ( what should be used) and why.

I strongly recommend that you buy a copy of QuickLoad and spend the time to learn to use it properly. It can be a real eye-opener.

With less case capacity , higher pressure, and a short barrel how does one choose what is the best propellant to make this work harmoniously

Same answer. QuickLoad. Best money I ever spent other than the $10 for a marriage license.

Listen to DB!

 

[bobcat93]

I will look into purchasing the program. It looks very complicated..