Is powder scalable? IMR 4198. Can you estimate bullet loads?

[PendletonCowboy]

I have came across several occasions where the load data is missing for the bullet grain that I need. It seems there is more data for the heavier loads than the light ones. So I ask you, can you scale the load data down or up for that particular powder to the bullet you are trying to load for? To me it seems logical and doable. Below are the bullets I would like to scale to given the data I have for the 80,90 and 100 grain bullets for a .243.

Speer IMR 4198

50 grain - 13.0 - 15.0?
55 grain - 13.5 - 15.5?
60 grain - 14.0 - 16.0?
70 grain - 15.0 - 17.0?
80 grain - 16.0 - 18.0 (Data from Speer)
90 grain - 17.0 - 19.0 (Data from Speer)
100 grain - 18.0 - 20.0 (Data from Speer)

Thanks for the feedback!

 

[RoostRider]

In simplest terms NO

You can safely go below the load data to a certain extent (obviously, at some point the round will no longer function properly).

Going over the load data you have can be dicey, and should be practiced with care because different powders react differently under different pressures. Different powders, bore diameters, cases, bullets, bullet weights, bullet shapes, and even to some extent primers, will each affect the pressures.

That being said, the loads you hope to produce may or may not be safe (I am not speaking to that). Hopefully someone who loads similarly will come along and tell you on that part.

 

[R.W.Dale]

IMO these stupid 20% load density gallery loadings are a damn good way to blow up a perfectly good firearm. I honestly don't understand what grown men's fascination with these infernal rifle destroying loads are.

Ive seen and read more reports on KB'd rifles from shooting these kind of loads than all other causes combined and multiplied x2 At one time I used such loads but no longer will I play Russian roulette with my guns and face

and to answer your thread title, NO

 

[rcmodel]

No, not really.

If you can't find data for a specific powder with a certain bullet weight?
That's what we like to call a clue the powder is wrong for use with that bullet weight.

In your example with Speer Reduced Load data using IMR-4198?
They only provide Reduced Load data with heavier bullets that will build & maintain enough pressure to insure getting them out of the bore in a predictable manner at relatively low velocity for the caliber.
Very likely the light bullets would not provide sufficient bore friction to get a good consistent burn.

At any rate, if you want to try it with those published reduced loads, there would be no safety reason to reduce the charge any further with lighter bullets.

Just guessing though, as we have no ballistics lab tests to prove it.

rc

 

[zxcvbob]

You forgot to say "tarnation" and/or "dagnabbit"

 

[PendletonCowboy]

The data I got was sent to me by Speer and on it was written Speer #14 manual. They didn't list any pressure with the data on any of the loads only listed muzzle velocity.

80 grain w/16 grn = 1801, w/18 grn = 2037.

I have not looked to see when that manual was published and figure they didnt have a lighter grain bullet at the time.

 

[rcmodel]

Oh, they had 70, 75, 80, 85, 90, and 100 grain data in the 13th. manual.

But only tested reduced load data for the 85 grain and heavier bullets.

Again, the heavier bullets provide enough friction to get a good powder burn, and enough mass to keep going through the bore once you get them moving.

True, light bullets have less bore friction.
But they also have less mass to insure they will keep going and make it clear of the bore when the low pressure load gets done pushing on them.

rc

 

[243winxb]

From your other post , i see your looking for a Youth Deer Hunting load for a 243 win. The load you posted(80 grain w/16 gr. 4198 = 1801 fps) should do, both for the deer and youth. If the kids cant handle this , they are not ready to hunt. My neighbors granddaughter shoots/hunts with a 243 win, factory loads, she is 9 years old.

 

[rcmodel]

Youth Loads?
Well shucks.

Why didn't you say so.

Rat Cheer is the safe way to do that.
http://www.hodgdon.com/PDF/Youth Loads.pdf

rc

 

[243winxb]

rc, he has that data already.

 

[PendletonCowboy]

Thanks much for the replies, i appreciate the use of your knowledge. I have that youth load pdf from Hodgdon but can't for the life of me get my hands on H4895, been trying for a while.
My intent here is to create some light loads so my 12 and 10 yr old can get comfortable with thier new rifles and build the loads up as we progress to the hunting months. Being familiar and comfortable with the rifle will increase the harvest success and overall hunting experience, I hope!
243winXP - you are suggestioning that the load info for the 80 grain would work fine with a 55 grain?

Thanks guys...

 

[243winxb]

243winXP - you are suggestioning that the load info for the 80 grain would work fine with a 55 grain

No. Use the load Speer gave you using the 80gr bullet.

 

[Maj Dad]

Powley Computer

The Powley Computer used to be the advanced tool for wildcatters and DuPont (IMR) powders back in the day. It's still a good resource, and there is even an online version ( http://kwk.us/powley.html ) you can play around with. Other than that, pressure doesn't follow arithmetic/algebraic equations in loading increments; makes bad juju to try. A little interpolation can be useful in between known max & min loads, but caution is well-advised.

 

[Kernel]

^^^^
A Powley Computer doesn’t work that way. You don’t pick the powder. IT picks the powder for you. (Actually, it calculates an ideal burn rate, a number Powley called the “selection index“, that number then corresponds to a specific powder).

With a Powley Computer you can vary the charge weight up or down by adjusting the load density, but going below a load density of 75%, or so, is not advisable. Much below that and the model become unreliable. Bottom line, the Powley Computer is NOT a good tool for calculating vastly reduced velocity loads. Was never intended to be.

It is a great tool for finding an ideal powder for some weird bullet. Like one that is really, really, light. Or one that is really, really, heavy. But, again, it’s going to pick the powder. You can’t force it to use one powder over another.