Maven
07-28-2016, 02:10 PM
173192Several years ago, I purchased a used Green River Forge 20ga. smoothbore trade gun (a copy of a Barnett I think), but experienced too many hang fires to suit me. I then took it to a local BP builder/'smith to have the vent liner replaced with a Jim Chambers White Lightnin liner. Oddly enough, there was no improvement until I inadvertently opened the touch hole diameter...to the diameter of the copper wire in Romex cable! That sure fixed the problem, but it self primed and shot a nasty jet of gas and powder debris to the right; didn't affect accuracy though.
In May I decided to try replacing that enlarged vent liner with another White Lightnin liner (pretty easy, but not a 5 minute job), and rebrown the entire bbl. while it was out of the stock. (I used Laurel Mt. Forge browning solution, which I'd rate 10 out of 10 pts. for ease and effectiveness.) Btw, the browning turned out great. Anyway, Wednesday was the first time I test fired it, and am happy to say that the gas jet and self priming have been eliminated, but there's still an occasional delay before the main charge goes off. A sharp flint and damp swabbing the chamber area after 5 shots help, as does using a vent pick on occasion.
As for accuracy, I was using a .597" patched round ball* + a corrugated cardboard over powder wad and 70gr. Wano FFFg and had little trouble hitting clay pigeons or parts of them @ 25yd. kneeling with my right arm on the bench. Although it was too hot for an extensive test, I did manage to put 3 shots in less than 3"on a NMLRA postal match target before a thunderstorm ended any further shooting. I'm OK with that as the gun has no rear sight, so it's a matter of cheek weld, consistent hold & trigger pressure, and follow through. Btw, the gun does equally well with patched RB's of .597" - .600" diameter, but nothing larger, Additionally, it's not a big fan of a bare ball with over powder and over shot wads or tow wads fore and aft either.
Yesterday, with no thunderstorms in the forecast, I took the trade gun to the range for a second trial. This time I damp swabbed the breech only after the first 5 shots (no crud ring or powder chunks!) and pricked out the touch hole for most shots. I was rewarded with just one fairly brief hang fire and pretty good accuracy (see the attached photo**). I also increased the charge slightly to 75gr. as I mixed a few ounces of Graf's/Wano FFFg into my Diamondback FFg, mostly to use it up in a sensible manner. Btw, I normally use 80gr. Diamondback FFg. In addition, I substituted Lee Precision .60cal. RB's (.598") for the Tanners, as I was running out of the latter. The Lee mold casts beautifully, and has the added advantage of a sprue cutter/plate. Both the Lee and Tanner molds cast a ~318gr. -.320gr. ball.
*.018" pillow ticking patch. A thicker patch in a smoothbore just makes it harder to start and seat a ball with little overall improvement in accuracy. Patch lube was 1 Ballistol : 6 water.
**17 shots @ 25 yd. Hit @ 6 0'clock was the minor hang fire. Shifting position of the sun (on the front sight) may help explain the shift in impacts to the right.
In May I decided to try replacing that enlarged vent liner with another White Lightnin liner (pretty easy, but not a 5 minute job), and rebrown the entire bbl. while it was out of the stock. (I used Laurel Mt. Forge browning solution, which I'd rate 10 out of 10 pts. for ease and effectiveness.) Btw, the browning turned out great. Anyway, Wednesday was the first time I test fired it, and am happy to say that the gas jet and self priming have been eliminated, but there's still an occasional delay before the main charge goes off. A sharp flint and damp swabbing the chamber area after 5 shots help, as does using a vent pick on occasion.
As for accuracy, I was using a .597" patched round ball* + a corrugated cardboard over powder wad and 70gr. Wano FFFg and had little trouble hitting clay pigeons or parts of them @ 25yd. kneeling with my right arm on the bench. Although it was too hot for an extensive test, I did manage to put 3 shots in less than 3"on a NMLRA postal match target before a thunderstorm ended any further shooting. I'm OK with that as the gun has no rear sight, so it's a matter of cheek weld, consistent hold & trigger pressure, and follow through. Btw, the gun does equally well with patched RB's of .597" - .600" diameter, but nothing larger, Additionally, it's not a big fan of a bare ball with over powder and over shot wads or tow wads fore and aft either.
Yesterday, with no thunderstorms in the forecast, I took the trade gun to the range for a second trial. This time I damp swabbed the breech only after the first 5 shots (no crud ring or powder chunks!) and pricked out the touch hole for most shots. I was rewarded with just one fairly brief hang fire and pretty good accuracy (see the attached photo**). I also increased the charge slightly to 75gr. as I mixed a few ounces of Graf's/Wano FFFg into my Diamondback FFg, mostly to use it up in a sensible manner. Btw, I normally use 80gr. Diamondback FFg. In addition, I substituted Lee Precision .60cal. RB's (.598") for the Tanners, as I was running out of the latter. The Lee mold casts beautifully, and has the added advantage of a sprue cutter/plate. Both the Lee and Tanner molds cast a ~318gr. -.320gr. ball.
*.018" pillow ticking patch. A thicker patch in a smoothbore just makes it harder to start and seat a ball with little overall improvement in accuracy. Patch lube was 1 Ballistol : 6 water.
**17 shots @ 25 yd. Hit @ 6 0'clock was the minor hang fire. Shifting position of the sun (on the front sight) may help explain the shift in impacts to the right.