What fps variation could I expect on the chrony with the same charge?

[tpcollins]

I read an article on finding the best load but it was for rifle cartridges not ML. The guy would start 1.5 grains below maximum and shoot 10 shots increasing the charge .2 grains at a time. He would look for spots where the fps for those increments stayed about the same and then worked on that range more thorough.

But I’ve ran my ML shots thru a chronology in the past and I’m sure I had weighed them at 70% for BH209. I’ve seen an inconsistent 50 fps over 6-7 shots with one being over 100 different. And I use a force gauge and seat the 250gr Barnes consistently with 60# of pressure.

I would think after successive shots the pressure would increase and give a higher velocity but that doesn’t seem to be correct. So if I can’t get fps to stay relatively close, is it the nature of the ML or just me?

If I can’t see a trend like the illustration below then probably the best route might be a 10 shot ladder test and look for a consistent node there. Thanks.

 

[Semisane]

For comparison, here's a velocity study I did with Blackhorn last March.

 

[Chris W.]

The last chronograph testing I did was with my optima pistol using BH209. I measured by volume not weight. I did two 3 shot strings....one using 85 gr and the other 90 gr. The spread on one three shot string was 38 fps. The other was 39 fps.

 

[Widude]

If you want some fun, test some ‘Shockey’s Gold’ or American Pioneer powder with the crony. With my buddy he had swings well over 200 FPS, while B209 was under 50.

I didn’t load his gun, so can’t vouch for consistency. His average FPS was also well behind B209, same charge & bullet weight.

 

[tpcollins]

Semisane - nice chart. The 73.5 gr looks similar to the intent of chart I posted.

 

[MSalyards]

I shot my CVA Accura v2 over a chronagraph using 77 weighed gr of BH209. Win blue box primers, Speer 300 gr deep Curls.452. Harvester Blk Crushribs. 5 shots were 4 @ 2028fps and 1 at 2034fps. I did not weigh the bullets .

 

[Busta]

I read an article on finding the best load but it was for rifle cartridges not ML. The guy would start 1.5 grains below maximum and shoot 10 shots increasing the charge .2 grains at a time. He would look for spots where the fps for those increments stayed about the same and then worked on that range more thorough.

But I’ve ran my ML shots thru a chronology in the past and I’m sure I had weighed them at 70% for BH209. I’ve seen an inconsistent 50 fps over 6-7 shots with one being over 100 different. And I use a force gauge and seat the 250gr Barnes consistently with 60# of pressure.

I would think after successive shots the pressure would increase and give a higher velocity but that doesn’t seem to be correct. So if I can’t get fps to stay relatively close, is it the nature of the ML or just me?

If I can’t see a trend like the illustration below then probably the best route might be a 10 shot ladder test and look for a consistent node there. Thanks.

View attachment 5882

Tim, you probably forgot to index you're sabots? That can give you inconsistent velocities.


Post #7 in this thread. Scum Bucket blurred the pics.

https://www.modernmuzzleloader.com/...le-but-knight-got-this-right.9003/#post-70371


Post #6 in this thread.

https://www.modernmuzzleloader.com/threads/sabot-indexing.12481/#post-99208

 

[tpcollins]

Thanks Busta - I remember this from long ago and I have an indentation on the muzzle to align the sabots against. I even made a little tool to help hold the sabot to align it correctly in the barrel’s “quick load” section - but I didn’t use it, I just eyeballed it at the range. Duh.

I’ll play with that today and make sure I verify where to exactly align the sabot to have 2 lands on each petal. Thanks.

 

[Sideshow]

I read an article on finding the best load but it was for rifle cartridges not ML. The guy would start 1.5 grains below maximum and shoot 10 shots increasing the charge .2 grains at a time. He would look for spots where the fps for those increments stayed about the same and then worked on that range more thorough.

But I’ve ran my ML shots thru a chronology in the past and I’m sure I had weighed them at 70% for BH209. I’ve seen an inconsistent 50 fps over 6-7 shots with one being over 100 different. And I use a force gauge and seat the 250gr Barnes consistently with 60# of pressure.

I would think after successive shots the pressure would increase and give a higher velocity but that doesn’t seem to be correct. So if I can’t get fps to stay relatively close, is it the nature of the ML or just me?

If I can’t see a trend like the illustration below then probably the best route might be a 10 shot ladder test and look for a consistent node there. Thanks.

View attachment 5882

Blackhorn is said to be optimal at 70 to 80lbs . I use a "powder packer" tool that is 75lbs . No chrony yet but my groups tightened using it .

 

[HC]

Who says? Maybe the company that makes the “powder packer” ? There has been discussions and experiments about packing powder for years.

 

[ENCORE50A]

I "pack" my BH at around 106#

 

[Sideshow]

Who says? Maybe the company that makes the “powder packer” ? There has been discussions and experiments about packing powder for years.

All i know is my groups tigbtened . I said that cause seeing was believeing . Consistant velocity tends to help tighten groups . Thats well respected truth , even without a chrony .

 

[tpcollins]

"Blackhorn is said to be optimal at 70 to 80lbs . I use a "powder packer" tool that is 75lbs . No chrony yet but my groups tightened using it “.


Years ago I was using my force gauge to pack BH209 to about 90#, but the last couple of years I dropped it down to 60#.

I’ll try going back to 90# again.

 

[Sideshow]

"Blackhorn is said to be optimal at 70 to 80lbs . I use a "powder packer" tool that is 75lbs . No chrony yet but my groups tightened using it “.


Years ago I was using my force gauge to pack BH209 to about 90#, but the last couple of years I dropped it down to 60#.

I’ll try going back to 90# again.

View attachment 5935

Thats a really fancy gaget you got there ...
Where did you find that gem ???

 

[ENCORE50A]

Thats a really fancy gaget you got there ...
Where did you find that gem ???

There's a huge difference in force gauges and their quality. Good ones are not cheap.
Just google force gauge. I would suggest a manual over digital.
There's also a right way to use them if you're checking loading force and not just seating forces.

 

[Sideshow]

There's a huge difference in force gauges and their quality. Good ones are not cheap.
Just google force gauge. I would suggest a manual over digital.
There's also a right way to use them if you're checking loading force and not just seating forces.

View attachment 5936

Thank you..... may just have to step up my game...

 

[Sideshow]

There's a huge difference in force gauges and their quality. Good ones are not cheap.
Just google force gauge. I would suggest a manual over digital.
There's also a right way to use them if you're checking loading force and not just seating forces.

View attachment 5936

Just a quick peek on google and Holy Cow your not kiddin !!!!! That is the cat's meow though...... Damn !! Too many irons in the fire !!!!!!!!!! I wooonnnddeer if moma would miss tbe bathroom scale THAT much.....you know when its in that room its really called the "LIAR" anyhow , at least thats what i holler at it .....

 

[ENCORE50A]

Thank you..... may just have to step up my game...

For 95% of shooters, a force gauge just isn't needed and money would be better spent on other items. If you're sizing and shooting land riding bullets of different types and weights, then maybe so.
I've had and used many different types of them when I was working as part of my job function. Quality is never cheap.

 

[Sideshow]

For 95% of shooters, a force gauge just isn't needed and money would be better spent on other items. If you're sizing and shooting land riding bullets of different types and weights, then maybe so.
I've had and used many different types of them when I was working as part of my job function. Quality is never cheap.

Oh i know !!! I have an A--bolt that is nearly done with 2 bartlein barrels(switch rig) so my budget is kinda tight for a bit . I will have one eventually !!! Believe im gonna need one . Besides , she caught me sneakin out to the garage with the "lying force gage" i previously mentioned ....took it to the range too and woulda got away with it but i brought it home and put it back muddy .....Lol , sorry , just cant behave myself this morning.....

 

[Sideshow]

For 95% of shooters, a force gauge just isn't needed and money would be better spent on other items. If you're sizing and shooting land riding bullets of different types and weights, then maybe so.
I've had and used many different types of them when I was working as part of my job function. Quality is never cheap.

Ok enough jokeing
Grainger has a chinese mechanical model force gage to 100lb for $175 . EVERYTHING else is very high dollar . They claim 1% deviation (like that word) but can it be trusted ??? Still its all relavant data for the user anyhow . Sure beats 700+ on up . Figured id give a heads up on this one . Beats guessing !!! What do you think ???