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[hortonstn]

Do wide groove narrow land barrels with 1-66 twist require large powder charges for optimum
Accuracy?

[Jeff Murray]

You did not mention the caliber or groove depth.  Generally for larger calibers with a 1 in 66 twist, you can shoot a fairly wide range of charges and still get decent results.  You will likely find a charge that generates a specific velocity produces the most accurate results.  All of this depends on a good patch and ball combination.  If you are shooting a small caliber you may need to shoot a little heavier charge to get optimum accuracy with a slower twist.

[Daryl]

What's large?  My .69 has about equal, maybe barely wider grooves than lands, and a 66" ROT.  It shoots well at close ranges with 85gr. 2F and shoots well out to 200yards with
140gr. of today's 2F. In 1986, I had to load it with 165gr. to shoot well on plates to 300 meters(327yards) on the plates. That was also my hunting load for moose.  That rifle never
missed that plate, about 30" in diameter, shot offhand, but whomever shot it, me, Taylor or or friend Leatherbelly. They refused a second shot.
The charge has to do with rate of twist, nothing to do with land or groove width. Round balls are stabilized over a wide range of speeds and rates of twists.
Sometimes a gun shoots better with more powder, sometimes an identical barrel will shoot best with less. A loose ball and patch combination will usually shoot best with lighter loads.
Heavies loads may produce too much pressure for the loose combination to seal the gasses behind it, and thus burn or shred the patch, which will destroy accuracy.

[hortonstn]

Thanks

[Dphariss]

Do wide groove narrow land barrels with 1-66 twist require large powder charges for optimum
Accuracy?

In general? No. But in the same vein when a friend was running a plank rest “turkey” match some years back we often found that shooters would reduce their string length by increasing the powder charge. Now its possible to get “acceptable”(?) accuracy from rifles with lighter charges and if shooting large hit or miss targets the difference may never be seen in the scores. But if you are shooting scoring ring targets or string measure from a rest then it can REALLY tell. With 66 twist barrels in 50-54 90 grains of Swiss FFF  or 100 gr of fff Goex always works, several rifles over the years. 70-90 on the 50 perhaps. Don’t matter if is a equal land and groove like a Douglas or a wide groove like GM. Basically for 45-54 caliber 1/2 ball weight of powder +- is all you should need less might work but If I start testing a 54 its with 90-100 gr. Though back in the mid-1970s I had a Sharon 54 with a 72” twist that liked 120 gr. FFF. FF powder is something I have used very little of over the years in MLs except my 67 caliber rifle, 437 gr ball. It has a 80” twist and shoots great with about 1/3 ball weight of FF Swiss, 140 gr.  HOWEVER, the bigger the ball the smaller ratio of  powder to ball weight. AND once under 45-50 caliber the ratio may go up. A 32 may require 30-35 grains to shoot well while the ball is 47-50 grains.
Finally I think that twists slower than 48” for calibers under 58 are not needed. A 48” twist 50 will shoot good with this twist and 1/2 ball weight of powder.  Assuming that the rifle that TK Dawson and J Baird tested in “Hawken Rifles..” was a 48 twist then the 48 will work fine in a 54 as well.

Groove width SFAIK makes no difference except they are easier to load and allow a tighter fit. The myth that ML MUST shoot pure lead comes, IMO, from barrels with lands that are too wide and thus require a softer, somewhat smaller ball to make loading forced acceptable.

Dan

[Daryl]

Too, as far as tight loads go, the smaller the ball, the "less lead" there is that has to be "moved" & the easier they are to load with those combinations. The larger the ball, the more lead there
is to move and loading tightly gets more difficult.
There is a bit of a tradeoff there, as the larger the ball, the lower the actual pressure generated for normal loads and thus the looser the combination can be.  It's all experimentation, ain't it
GREAT!

[hortonstn]

Thanks for the info it's a 50 cal 42"long 1-66 twist  I'm going to range tomorrow for testing

[Daryl]

With decent loads getting up over 75gr. 3F or 80gr. 2F, a tighter load is usually necessary for longer range accuracy.

[hortonstn]

This is bench at 60 yds open sights
.018 teflon ticking i think I’ll use the
70 grains of swiss ff 500 ball
Thanks

[Daryl]

70 or maybe 75 might have been the best.

[Marcruger]

In my experience, 70 to 75 grains of 2f is a sweet spot for accuracy in a .50.
Btw, I was taught using teflon patching and wiping. One reason I stopped was looking up solvents for Teflon.  Bake it into the bore and it builds up.  I could find zero solvents that can remove it.
I also was convinced by Daryl’s explanations of wet lubing that it was a much better process.
Check out Teflon online. It’s an eye opener.
I now use Mr Flintlock as my lube and final cleaner.  It removed graphite.
God bless, Marc

[hanshi]

70 grains of 3F seems to punch the ticket in my .50 Rice radius groove barrel.  But I could increase that a bit and likely get about the same level of accuracy.  That same charge does the job in my .45s as well.

[hortonstn]

Marc
I agree with cleaning I run two spit patches between shots
I have Mr Flintlock and .18-.20 canvas that's my next test
Thanks for your info
Paul