Load development method?

[dk17hmr]

I ordered a 45 cal SML Remage barrel with the arrowhead breech plug and a swinglock die. It'll be a little while before I get all the parts together.

I'm curious how guys are working up loads.

I was thinking starting with 45-70 loads and laddering up while shooting with the Labrador.

How big of powder jump with smokeless .5gr? 1gr? Seems like most of the loads I'm seeing online are round numbers.

 

[ENCORE]

Good luck on your build.

Myself I like to do .5grs.

When I do my Satterlee tests, I graph them out. The graph below has the charges removed but, the charges were .5gr increases. There are two very distinct nodes as marked and both were at .5 marks.

 

[West Calamus]

On extruded powders move the decimal point to the left one place on the load for development. (4 grs on a 42.4 max. 0n a .243; 5 grs for a 270 with 53.2 grs.: 6 grs for a 300 wm. on 68 grains). Most ladder test starts at 10% of max. but I usually start at 2 or 3 gr under max. Ball powders may want to use 1/2 the amount on ladder development. ( 2 to 3 gr. so u do no quick pressure spikes).

 

[West Calamus]

oops move decimal 2 pts .4 or .5 or .6 grs

 

[dk17hmr]

Good luck on your build.

Myself I like to do .5grs.

When I do my Satterlee tests, I graph them out. The graph below has the charges removed but, the charges were .5gr increases. There are two very distinct nodes as marked and both were at .5 marks.

View attachment 360709

Same way I get close with with my centerfires...10 shot velocity and graph.

Are those legit velocity's?

 

[ENCORE]

Same way I get close with with my centerfires...10 shot velocity and graph.

Are those legit velocity's?

Yes, that's actual velocity.

 

[dk17hmr]

On extruded powders move the decimal point to the left one place on the load for development. (4 grs on a 42.4 max. 0n a .243; 5 grs for a 270 with 53.2 grs.: 6 grs for a 300 wm. on 68 grains). Most ladder test starts at 10% of max. but I usually start at 2 or 3 gr under max. Ball powders may want to use 1/2 the amount on ladder development. ( 2 to 3 gr. so u do no quick pressure spikes).

It sounds like you are saying use 90% of max and work up 1% at a time. That's a decent method for centerfires when you have book loads, and generally the ladder method I do.

I'm curious on how that would apply with a smokeless muzzleloader when you don't necessarily have book loads. Depending on the rifle I have seen 45-70 to 458 lott powder charges posted.

 

[dk17hmr]

Yes, that's actual velocity.

That's very interesting that velocity is relatively flat over the charge range. Do substantial lower powder charges have greater gains or is it just gradually up?

 

[lancetkenyon]

Call Arrowhead rifles and ask them for their recommendations.
That is what I did.
I used the Arrowhead XLD 300gr .45cal bullets.
They gave me two smokeless powder choices. H322 and H4198. Plus, they game me the load range for each powder.
And their recommended charge weight with their preferred powder, H322.
I tried that load....and done. I have done 3 of their rifles to date. All 3 with their recommendations. All 3 are sub-half MOA at 100 yards, and 2 of the 3 have been shot out to 800+ yards.

They also have a BH209 load if you go black powder substitute. I can't find the photos of that load, but I am pretty sure it was 2598fps and same type of grouping as below.

Here are two of the ML rifles groups.

#1 (shots 1/2/3 from rifle)

#2 (shots 2/3/4 from rifle)

The projectile used in all 3 rifles.

Plus, shooting one of the MLs at 981 yards.

 

[ENCORE]

That's very interesting that velocity is relatively flat over the charge range. Do substantial lower powder charges have greater gains or is it just gradually up?

I think its the nature of that propellant. That chart has a range of 4grs.

This is a chart, also of an only 4gr increase but with Benchmark.

 

[Alibiiv]

oops move decimal 2 pts .4 or .5 or .6 grs

That could've been a dangerous "Oops!!"!!!

 

[Veteran]

Good luck on your build.

Myself I like to do .5grs.

When I do my Satterlee tests, I graph them out. The graph below has the charges removed but, the charges were .5gr increases. There are two very distinct nodes as marked and both were at .5 marks.

View attachment 360709

I think I would pick the 7th or 8th point from the left, because the whole region from 6 to 9 is relatively flat, and you have more room for charge weight variance to the left and right that way and more room for temperature variance on burn rate too.

Also, I recommend a more finely granular chart scale. Its hard to see slope changes on the curve with 500 fps graduations. How does this curve look at 25 fps graduations?

 

[ENCORE]

Good luck on your build.

Myself I like to do .5grs.

When I do my Satterlee tests, I graph them out. The graph below has the charges removed but, the charges were .5gr increases. There are two very distinct nodes as marked and both were at .5 marks.

View attachment 360709

NOTE:............ ACTUAL PROPELLANT IS IMR8208XBR. I forgot to change it on the graph.

 

[ENCORE]

I think I would pick the 7th or 8th point from the left, because the whole region from 6 to 9 is relatively flat, and you have more room for charge weight variance to the left and right that way and more room for temperature variance on burn rate too.

Also, I recommend a more finely granular chart scale. Its hard to see slope changes on the curve with 500 fps graduations. How does this curve look at 25 fps graduations?

Can't remember how to change the chart to only 25fps