Importance of Load Devolopment

[PastorB]

I've had a .54 Cabelas/Investarms "Hunter Hawken" sitting around for a couple of decades collecting dust. Chromed barrel with a 1 in 48" twist. Since my eyesight has deteriorated due to age, I find it difficult to shoot decent groups with any of my rifles nowadays. Still "Minute of Deer", but the days of shots touching, except by random chance, have been gone for a while. This is where the old dust collector becomes relevant. Since I never used it anyways, I decided to mount a Lyman 57 peep sight on it, and see if that helped my shooting any.

Using .530 round balls, 60 grains Pyro P and. 020 linen patches, I placed 3 shots touching at 50 yards. Pretty stoked about that accuracy, but velocity was relatively low at 1400fps. So I upped the charge to 70 grains, using the same components, and put three balls thru the same hole at 50 yards. Really excited about that! However, the velocity was still lower than I would like, about 1500fps or so. The next logical step was to use 80 grains, which I proceeded to do. My group turned into a 15" pattern, thought something had come loose, so checked everything and found it all ok. Fired another 3 shots, dropping back to 70 grains, all holes touching.

I tried many more shots using other powders and varying patch thicknesses, and also employed a felt wad on top of the powder. Anytime the velocity exceeded 1500 fps, the "group" exploded in size. Dropping down underneath that threshold, the shots were stacking one on top of another. I guess my max load will be whatever powder charge gives me 1500 fps, and no more. Oddly enough, Hodgdon 3f 777 was slower that 3f Swiss and Pyro P, it is usually significantly hotter, and it was a brand new can. Tried several shots with the 320 grain Lee REAL, was not even on paper, so gave that up quickly. The conclusion is you had better develop a load and test it in your rifle before assuming your gun will hit where you aim it. I am content to have tack driving accuracy, and even at 1500 fps, that .530 ball will get any buck that I'll ever have the chance to take.

 

[necchi]

I have one of those,
Mine also liked 530 ball, I used an 020 denim patch with a dryish lube and close to 75grn of 2FT7 was it's favorite.
Never had a bit of trouble with that chrome bore, it made meat and won it's share in off hand competition.
I mounted a GM slow twist barrel on it in 54.

 

[Flint62Smoothie]

Good shooting! And I couldn't agree more … but don’t worry about chasing velocity.

I do the same, then bench them when I find a node to develop further. This target shows quite the variation (both in group size & point of impact) as the load changed …

 

[longcruise]

Did you inspect any of the patches?

 

[PastorB]

Did you inspect any of the patches?

Yup, they could have been re-used. I used a lubed wad over powder to protect the patch, as has become my standard practice in all my rifles. I have another Investarms Hawken in .54 (my first muzzleloading rifle, 1976) that is nearly identical, .54, 1 in 48", that shoots great with higher powder charges. Until the other day, the "Hunter Hawken" has had fewer than 50 shots thru it, I surpassed that total in one afternoon. Perhaps the chrome barrel, or some other variant, is letting the higher velocity PRB's "skip" the rifling. With the .020 patches, it loaded tight, and I find it unusual that it loses accuracy to such a substantial amount by slightly exceeding 1500 fps. I tried a lot of variables, and anything above that stated velocity just shot horrible, while about any load or patch combo that produced sub 1500 fps shot very well. Go figure. I have never experienced that drastic a change in accuracy with any reasonable load in any gun.

 

[necchi]

I find it unusual that it loses accuracy to such a substantial amount by slightly exceeding 1500 fps

It's not really so unusual, even in modern arms load development.
It's tough with our hand loaded trad ml's because the same variables could be used by a different person and have different results, simply because of the way he "drives" and "seats" the combo. Truth.
I use 5grn increments for charge development, then address the lube variable while fine tuning a load. Could be your change for more velocity is in the patch thickness or lube,,(?)
Non the less, Thank you for sharing the topic of load development being needed to tune these thing's.
So many of those new to the sport think/expect it to be "off the shelf" data applied,,,
And all of that, is why I got into to this stuff in the first place,, I wanted to be challenged again,,

 

[longcruise]

This is very odd. An effect with no apparent cause.

I find it hard to resist trying to figure these things out. We've covered so many bases but there's something we missed.

 

[yonderin]

Accuracy is achieved by the projectiles leaving the bore at the same place in the barrel harmonics, finding that sweet spot that does it to our satisfaction. Change one thing and you may well have to change something else as well. We talk about 5 gr charge changes, cartridge shooters look at .1 gr changes. Our concern with seating a ball generally doesn't quite compare to their measurements in a couple 1,000 of an inch.

A thought, as long as you're comfortable with it, try increasing your charge by 5 grains a couple times. See if it'll come back into a sweet spot.

 

[TDM]

Nicely done @PastorB !!

 

[Flint62Smoothie]

We talk about 5 gr charge changes, cartridge shooters look at .1 gr changes.

Not really, as look up the Optimal Charge Weight (OCW) method pioneered by Dan Newbury. Like my 5-grn increment testing, he usually advises a larger increment, typically 2-3 grains - dependent on caliber - but again, different animals.

However, both the increment method I showed above, or the more exacting OCW method, finds the 'node' target range. Only then do you proceed with finer grain/charge increments around the node to really fine tune the load, but now at a distance. Applied to black powder, this is when you could also experiment with the amount of lube used (but not the type). Believe me ... it works!

When shot, regardless of arm type or caliber, the barrel whips in a sine wave manner, where the node is where the barrel is at the point(s) of the LEAST movement. That is when you want your shot to be fired. For some of us, good enough is good enough, but I do find this very interesting and fun to experiment with!

 

[PastorB]

Well, I returned to the range today sighting in my .54 "Hunter Hawken" and it's near twin, the .54 Charles Daly/ Investarms, that I've had since the mid 1970's. I replaced those atrocious factory adjustable sights on the Chuck Daly with a buckhorn rear and brass blade up front. Really haven't shot either of these rifles much in the last 30 years, as I got "better" ones that took their place. After today, these old rifles are going to start coming out more often.

As stated in my thread starter, the Hunter Hawken wouldn't group with any load over 60 grains, but it was placing those PRB's thru the same hole at 50 yards. Today I sighted it in at 100 yards, and couldn't believe the group I shot. Three shots touching, maybe 5/8" center to center, smack dab in the Bullseye! Yup, I'm proud of that! Couldn't believe it until I walked down range and saw the results. It was not possible to see where the balls were hitting from the bench at 100 yards. The pic shows three groups, unmarked was 4 Lee REAL bullets, the one with lines connecting was with 70 grains of powder and a PRB, and the clover leaf (actually 4 holes, one shot is from the 70 grain group) is 60 grains Swiss 3f, a .020 patch, and a .530 roundball. I will never load any other combo in this rifle again! Velocity was very consistent, 1490 fps 6 yards from the muzzle, with an extreme spread of 7 fps. I found my load for the "Hunter Hawken".

The old CD "Hawken" has always been a great shooter, just wasn't as sexy as my "better" rifles I have since acquired. It has always shot really well, as I used to shoot squirrels in the head with my young eyes. Today with 90 grains of 3f Swiss and the PRB (1700 fps), it shot MOA at 100 yards. Don't usually like that high of a charge, but I do like the accuracy! It printed 5" high at 100 yards, but I can file down my rear sight to remedy that. Needless to say, I was super impressed by the capabilities of these cheap old rifles, and they will be getting shot a lot more in the future.

 

[chorizo]

"... been a great shooter, just wasn't as sexy as my "better" rifles"

To rephrase, the only sexy rifle is an accurate rifle!

 

[Flint62Smoothie]

FYI, due to some PM questions, I've updated my picture to more clearly illustrate why finding the accuracy node of any firearm that shoots a projectile (BP or modern) is so critical to accuracy, i.e., you want to find the load charge where the load exits the muzzle - which is vibrating like a tuning fork - at the moment of its least movement possible.

Note short fat barrels are more forgiving in that you can see it would be possible to find an accuracy node at the 'middle' of the total movement range. In fact, I've proven that with a 31" heavy barreled Jaeger I have where loads spanning 15-grains all shoot 1-hole groups. My plan is to take that rifle out to 100-yards to see difference on paper between those charges within that +/- 7.5 grain range.

Fun facts - In MZl'drs so far I've found 3 accuracy nodes - which is cool, using one 48" barreled musket as the example ... as I then got a low power (say 45-grn) load - a mid-power (65-grns) load and a higher power hunting load (~85-grns). With 'other' modern rifles, some will find up to 6 nodes, which is why we then further tune at distance, some out to 1,000 yards!

View attachment 361797

 

[WALT53]

FYI, due to some PM questions, I've updated my picture to more clearly illustrate why finding the accuracy node of any firearm that shoots a projectile (BP or modern) is so critical to accuracy, i.e., you want to find the load charge where the load exits the muzzle - which is vibrating like a tuning fork - at the moment of its least movement possible.

Note short fat barrels are more forgiving in that you can see it would be possible to find an accuracy node at the 'middle' of the total movement range. In fact, I've proven that with a 31" heavy barreled Jaeger I have where loads spanning 15-grains all shoot 1-hole groups. My plan is to take that rifle out to 100-yards to see difference on paper between those charges within that +/- 7.5 grain range.

Fun facts - In MZl'drs so far I've found 3 accuracy nodes - which is cool, using one 48" barreled musket as the example ... as I then got a low power (say 45-grn) load - a mid-power (65-grns) load and a higher power hunting load (~85-grns). With 'other' modern rifles, some will find up to 6 nodes, which is why we then further tune at distance, some out to 1,000 yards!

View attachment 361797

I’d say that your find goes for every gun even smoothbores ,you gotta shoot em to find what the particular gun likes .