Contined shot load testing - .62cal Flint smoothbore

[roundball]

08/30/08
Continued shot load testing in .62cal Flint smoothbore, Jug Choked Imp. Cyl. ”˜Plus’
Last trip I tested 1+3/8oz copper plated #6 and they patterned perfectly.
This trip I tested magnum 7.5’s, both 1+1/8oz & 1.0oz loads, which also patterned perfectly.
With 7.5’s pellet count, I can easily use the 1oz load for Doves in this .62cal Flint smoothbore.
Pattern test chart shows averages of 1+1/8oz and 1oz loads at 35yds.

 

[MSW]

RB- thanks for doing all this 'grunt work!' I know that you can probably get this in a reloading manual, or maybe not, or get near a theoretical approximation of the data, but it's really good to see someone without any vested interest in the result run the test. With (and no slap intended at manufacturers) the reloading manuals, you get data from (usually) thier product and it's usually putting the best foot foreward. With your work, we get what actaully happens in the field.

Which data is more likely to put meat in the freezer?

I go with your info every time.

Thanks again!

 

[roundball]

Agree with the point about manual references, and feel the same way about arm chair theories...there are too many variables, not the least of which are the operators themselves ( :grin: ) so to me they don't have much value until I can prove to myself first hand that it works for me in my barrels, etc.

In fact, a couple of things are worth noting right here from actual hands on experience with 'Jug Choked' barrels:

#1
The performance of the 1oz load is just outstanding, yet flies somewhat in the face of conventional wisdom...normally using equal measures of powder & shot, or more shot than powder produce the best results in smoothbore...but in this case there is more powder than shot. And that should provide excellent velocity which is a good thing for wing-shooting of course...one of these days maybe I'll get up the nerve to shoot the load through my chronograph.....(maybe :wink: ).

#2
The other thing worth noting with all my tests in these jug choked barrels is that the effects of various wad configurations seem to work in reverse from conventioal wisdom...ie: I have to use a single 1/8" Oxyoke wad for an open pattern...and if I go to a full 1/2" cushion wad, the pattern tightens up as if its become a full choke.

I conclude that the shot charge reaches the Jug Choke expansion chamber while the bore is still sealed behind it from the longer 1/2" wad, for a longer period of time...less disruption from gas pressure blowing around a smaller wad while the shot charge is still in the early stages of the expansion chamber...dunno...but using a larger, heavier, taller cushion wad in this Imp.Cyl.'Plus' Jug Choked barrel produces a noticable tightening of the pattern...opposite from what normally happens in a straight cylinder bore barrel when a larger heavier wad is used.

A Jug Choke is the one of the best $75 I've ever spent and whole heartedly recommend them...use magnum lead, or better yet copper or nickel plated shot to minimize deformation from a bare bore, and you have an outstanding performing smoothbore at distance...just load powder/wad/shot/card.

( wish I could find a gunsmith with a machine shop who could create a jug choke in a .54cal/.28ga barrel...so far, no luck)

Pattern paper at 35 yds...pretty strong pattern from a 1oz load at that distance, no shot cup...good dove load

 

[rkmeyer]

Roundball,
Thanks for the information. I just finished a 20 ga jugged to mod. but have not shot it yet. It's at our county fair, got Best in Show with it and the next test will be at the pattern board. The fair ends today.
Dusty

 

[Joel/Calgary]

It's interesting to see your results.

Agree with the point about manual references, and feel the same way about arm chair theories...there are too many variables, not the least of which are the operators themselves ( :grin: ) so to me they don't have much value until I can prove to myself first hand that it works for me in my barrels, etc.

Most of us would agree. Both theory and other folks experience can be useful, but you can't trust them absolutely without testing in YOUR circumstances.

In fact, a couple of things are worth noting right here from actual hands on experience with 'Jug Choked' barrels:

#1
The performance of the 1oz load is just outstanding, yet flies somewhat in the face of conventional wisdom...normally using equal measures of powder & shot, or more shot than powder produce the best results in smoothbore...but in this case there is more powder than shot.

That actually agrees with some things I recall noticing in 18th & 19th century load info. Before chokes, with the static shot charge in a cylinder bore, recommended loads were no more powder than shot (except to specifically open the pattern) and one reduced powder to tighten the pattern - the "1/3rd more shot than powder by volume" load being the widely recommended optimum between velocity and pattern. With a 1&1/8oz. shot charge, 2&3/4drams of powder is the equal volume load and 2dr. is the "1/3rd more.." load.

After chokes became standard, it appears that somewhat more velocity was found to give better patterns with the much more complex dynamics of a shot charge going through a constriction. This was occasionally opined in print, and almost all common loads recommended (M/L or cartridge) or loaded in cartridges went to equal-volumes or higher. The most common 1&1/8oz. load became 3dr and sometimes 3&1/4dr, with 2&3/4dr loaded for lower recoil, and rarely was any less powder used.

#2
The other thing worth noting with all my tests in these jug choked barrels is that the effects of various wad configurations seem to work in reverse from conventioal wisdom...ie: I have to use a single 1/8" Oxyoke wad for an open pattern...and if I go to a full 1/2" cushion wad, the pattern tightens up as if its become a full choke.

I conclude that the shot charge reaches the Jug Choke expansion chamber while the bore is still sealed behind it from the longer 1/2" wad, for a longer period of time...less disruption from gas pressure blowing around a smaller wad while the shot charge is still in the early stages of the expansion chamber...dunno...but using a larger, heavier, taller cushion wad in this Imp.Cyl.'Plus' Jug Choked barrel produces a noticable tightening of the pattern...opposite from what normally happens in a straight cylinder bore barrel when a larger heavier wad is used.

I've seen this noted before more than once, but I can't recall by whom (CRS syndrome again). Sometimes a very long wad column was used to keep the gasses sealed longer. With the wad keeping powder gasses out of the shot longer in the jug choke, some authors think that, even in a jug choke, friction with the choke slows the heavier wads enough to reduce interference with the back end of the shot cloud. I've also seen shot protectors, even paper ones, recommended in jug chokes to help keep the powder gasses out of the shot.

I found it interesting in your previous testing that the wheelweight-hard "Nice Shot" patterned even tighter than the hard lead shot, too.

Joel

 

[roundball]

Roundball,
Thanks for the information. I just finished a 20 ga jugged to mod. but have not shot it yet. It's at our county fair, got Best in Show with it and the next test will be at the pattern board. The fair ends today.
Dusty

Be interesting to see if there are any similarities in pattern behavior with respect to the wads.

Also, I'd ordinarily expect your pattern to be tighter with a modified choke...I asked for mine to be Imp. Cyl. 'PLUS'...halfway between IC and Modified...but judging from the patterns I'm getting, I'm wondering if it might be a complete modified...throws a pretty dense pattern at 35-40 yards.

 

[roundball]

"...some authors think that, even in a jug choke, friction with the choke slows the heavier wads enough to reduce interference with the back end of the shot cloud..."

They may be thinking about conventional chokes which operate on the principle of "constriction"...where-as the jug operates using an expansion chamber larger than bore diameter so I don't think there would be any friction contact with the wads.

I've also seen shot protectors, even paper ones, recommended in jug chokes to help keep the powder gasses out of the shot.

Seems if the shot column was confined in a shot cup, then it would sail right through a jug choke's expansion chamber and not get any choking effect ??

I found it interesting in your previous testing that the wheelweight-hard "Nice Shot" patterned even tighter than the hard lead shot, too.

And substantially so....54-58 average pellet compared to 80...that's a pretty big jump...I think the holes cost about a dollar apiece ! :grin:

 

[bingo1952]

"...some authors think that, even in a jug choke, friction with the choke slows the heavier wads enough to reduce interference with the back end of the shot cloud..."

They may be thinking about conventional chokes which operate on the principle of "constriction"...where-as the jug operates using an expansion chamber larger than bore diameter so I don't think there would be any friction contact with the wads.

I've also seen shot protectors, even paper ones, recommended in jug chokes to help keep the powder gasses out of the shot.

Seems if the shot column was confined in a shot cup, then it would sail right through a jug choke's expansion chamber and not get any choking effect ??

I found it interesting in your previous testing that the wheelweight-hard "Nice Shot" patterned even tighter than the hard lead shot, too.

And substantially so....54-58 average pellet compared to 80...that's a pretty big jump...I think the holes cost about a dollar apiece ! :grin:

You will get resistance once the wad hits the front end of the jug choke where it goes back down to bore size. Maybe not much but it seems to be enough to keep the wads from blowing the patterns. Congrats on the upping of your pellet count. :thumbsup:

 

[Joel/Calgary]

I've also seen shot protectors, even paper ones, recommended in jug chokes to help keep the powder gasses out of the shot.

Seems if the shot column was confined in a shot cup, then it would sail right through a jug choke's expansion chamber and not get any choking effect ??

Except maybe for the really stiff steel/tungsten shotcups, the information I've seen suggests that there's enough time for regular (for lead shot) & home-fabricated shot cups to open out then get squeezed back. Given the possibility of shot leakage between the petals when the cup expands, I wouldn't try it with the hard shot except with a shotcup with overlapping petals or *maybe* with a mylar wrap inside.

Joel