Trajectory of a Foster Slug

[SubieGuy4]

Recently learned about what Point Blank Range really means (http://www.arld1.com/images/swfs/trajectorypbr2.swf) and am now looking to determine MPBR for all my guns based on their intended purpose (bad guys for the AR, small game for the .22, and large game for the 12ga when using slugs).

I'm looking for resources that can help me plot the arc of a 12ga 1oz foster slug based on various zeros so I can determine the MPBR and optimal zero for my purposes.

Alternatively if anyone knows the BC of a 1oz foster slug and a 1-1/4oz foster slug I can probably do my own calculations with this: http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

 

[mac1911]

think you will find these slugs BC to be low.... say .100 or less.
quick look on federal they list theres at .109
My dad zeroed my 870 smooth bore slug barrel with the remington sluggers 20+ years ago. want to say it was 35ish yards. I know from 0-75 yards if I hold on the kil zone im going to hit it. a tad low at 75 yards... @ 100 yards I need to hold high, although I have and probably would not take a shot at a deer @ 100 yards with my 870 slug barrel. Heck in the woods im lucky to even see a deer beyond 60 yards.

 

[arlow]

2" high at 75 yards will be just about dead on at 100. Thats about as far as you wanna shoot with fosters if, and that is a big if, you have a gun that can spit it out that far accurately. I had one smoothbore , winchester 1300 with a smoothbore deer barrel, that I could group at 4 inches consistantly at 100 yards with remington sluggers. Most smoothbores wont do that and you have to limit your range to whatever you can group well at.

 

[SubieGuy4]

2" high at 75 yards will be just about dead on at 100. Thats about as far as you wanna shoot with fosters if, and that is a big if, you have a gun that can spit it out that far accurately. I had one smoothbore , winchester 1300 with a smoothbore deer barrel, that I could group at 4 inches consistantly at 100 yards with remington sluggers. Most smoothbores wont do that and you have to limit your range to whatever you can group well at.

My 18.5" 870 barrel groups 5-6" at 100 yards. I wouldn't be shooting over 100 though. I do shoot plates at the range at 200 with good results but for practical purposes 100 is the max. Really want to actually plot the trajectory of the slug rather than making guestimations for zero and drop.

As as for that note that Federal says .109BC, their claimed
BCs are nonsense for every one of their rounds. They claim .338BC for XM193 when in fact it's more like .250.

 

[arlow]

I havent seen anything published for foster pumpkins. I only use a rifled gun now with light field sabots. They do have mpbr all mapped out for those rounds.

Sent from my SCH-I605 using Tapatalk

 

[SubieGuy4]

I havent seen anything published for foster pumpkins. I only use a rifled gun now with light field sabots. They do have mpbr all mapped out for those rounds.

Ya I realize most people don't plot precision ballistics for smooth bore guns lol.

 

[mac1911]

My 18.5" 870 barrel groups 5-6" at 100 yards. I wouldn't be shooting over 100 though. I do shoot plates at the range at 200 with good results but for practical purposes 100 is the max. Really want to actually plot the trajectory of the slug rather than making guestimations for zero and drop.

As as for that note that Federal says .109BC, their claimed
BCs are nonsense for every one of their rounds. They claim .338BC for XM193 when in fact it's more like .250.

I have heard BC on foster slugs to be as good as a engine block, By memory when my dad was into black powder more the Lyman black powder manual had round ball at a higher BC than slugs.....now rifled barrels with sabot thats another story all together. My friends rifle bolt action with some fancy (BP balistic ammo or something) bangs out clover leave groups at 100 yards with consistancy.
So I guess for BC you can pick a point between .000 and .100 ? I am pretty sure if your shooty and ammo can hold say sub 4" groups at 50 yards you should be able to nail the kill zone of a broad side shot of a white tail (9" inches or so). Once you find a ammo your gun likes of course. My 870 likes the rem sluggers and I can usually hit a 6" plate from 20-75 yards with a center hold...I am out of practice shooting the shooty since i stopped hunting though.

Fooling around with the only balistic calculator I have Hawke BDC ( i really only use it for my pellet guns). They have a reference to 12g foster slugs. Seems my dad was onto something 20+ years ago. The data it spits out with a 35yd zero you get to just about 70 yards before it drops off. Total drop for 75 yards was almost 3" aprox 2" low @ 20 yards

 

[SubieGuy4]

Only thing I've found online is a BC of .071. Haven't seen it from more than one or two sources though so hard to know. Using that measurement and the calculator I linked, the trajectory it plots seems very feasible. Not sure how precise it is though. My calculation based on that BC gives me an 85 yard zero with the slug at 2" high at 50 yards, zero at 85 and 2" low at 100 (and dropping about an inch every 5 yards from there on out). I think I'm going to re-zero for 85 on my next range day and then put targets at 25, 50, and 100 and see where the slugs go.

My setup will shoot 6MOA to 100 yards so obviously it will all be dependent on groupings too (radius of the group could be a larger deviation than the 2" low that it would be at 100 yards so it may all be irrelevant past about 75 yards.

 

[mac1911]

Only thing I've found online is a BC of .071. Haven't seen it from more than one or two sources though so hard to know. Using that measurement and the calculator I linked, the trajectory it plots seems very feasible. Not sure how precise it is though. My calculation based on that BC gives me an 85 yard zero with the slug at 2" high at 50 yards, zero at 85 and 2" low at 100 (and dropping about an inch every 5 yards from there on out). I think I'm going to re-zero for 85 on my next range day and then put targets at 25, 50, and 100 and see where the slugs go.

My setup will shoot 6MOA to 100 yards so obviously it will all be dependent on groupings too (radius of the group could be a larger deviation than the 2" low that it would be at 100 yards so it may all be irrelevant past about 75 yards.

Actual range time tells all. I never pushed the limits of my 870 and the rem slugs. I have been able to hit 6" plates out to 100 yards in the slug shoots my club used to have.

 

[whatluck]

I have an 870 with a smoothbore barrel. I hold the bead on target at about 75 yards and get center hits, about 4" groups with 3" magnum slugs. 100 yards seems like I aim less than 2 inches high. At < 10 yards I don't aim at all, I just point. Probably aiming pretty low though, could be a few inches or more.

 

[SubieGuy4]

I have an 870 with a smoothbore barrel. I hold the bead on target at about 75 yards and get center hits, about 4" groups with 3" magnum slugs. 100 yards seems like I aim less than 2 inches high. At < 10 yards I don't aim at all, I just point. Probably aiming pretty low though, could be a few inches or more.

Ya hitting targets isn't a problem here. My red dot is zeroed for 100 and I put the dot on the target and the slug hits. I'm trying to actually plot the highs and lows at every yard from the muzzle to 100 yards so I can determine the best zero and max distance at which the slug is never more than 2" high or 2" low of point of aim. Setting up my zero like this will make it so I don't have to think about distance and holdovers/holdunders. I can just put the dot on the target and know for sure it'll be within 2" high or low, which is easily the kill zone for larger game.

 

[mac1911]

I might be wrong but I am new to a lot of this myself. But I think if you zero your red dot to poa=poi I think it would be close to 20ish yards poa=poi
Then from 20yds or so out to 100yds you should be hitting only a few inches high maybe peaking around the 50-60 yards range at about 3" high?

 

[92G]

With my smooth bore 20" mossberg rifle using bead sight, i was able to connect at 100 yard gong fairly consistently (did it yesterday evening as i was bored)
shooting 1oz winchester slug rated 1600 ft/s
POA/hold was approx 8" high and 6" right of POI


dude at range didnt believe me it was smooth bore. He thought rifled for sure. I am no amazing shot...it really just shows if someone is methodical the correct POA can be found.