Does anyone have a working link to the JBM Small arms ballistics program / tables? Everything that google turned up was dead and I was unable to find any info on the 22lr at their main site: http://www.jbmballistics.com/
- Thread starter bubajoe
- Start date
Re: JBM Small Arms Ballistics working link?
I made a data sheet based off of other shooters data sheets and numbers for the BC that I found on the web and velocities from other shooters using similar length barrels and spaced it evry 1 yard out to 300 yards. It's almost spot on from a known 50 yard zero to a 100 yard zero. Maybe a little fine tuning on my part but other than that it's right on. At 200 yards it was pretty close as well. If you want, I can send you the file and you can take the info off of it and input that plus your own reletive info (altitude, air pressure, temperture, etc, etc...) and it 'should' be pretty spot on. Mine is for Wolf MT but the numbers for Eley isn't hard to find either with a little searching.
It's a really large file though so I don't want to bog down the site by directly posting it here. Anyone who wants it, let me know and I will PM it out to whoever asks for it.
Edit: I forgot to say, no, I don't know where the working link is if there even is one anymore. I tried, but couldn't find it when I had looked for it.
-Dylan
I made a data sheet based off of other shooters data sheets and numbers for the BC that I found on the web and velocities from other shooters using similar length barrels and spaced it evry 1 yard out to 300 yards. It's almost spot on from a known 50 yard zero to a 100 yard zero. Maybe a little fine tuning on my part but other than that it's right on. At 200 yards it was pretty close as well. If you want, I can send you the file and you can take the info off of it and input that plus your own reletive info (altitude, air pressure, temperture, etc, etc...) and it 'should' be pretty spot on. Mine is for Wolf MT but the numbers for Eley isn't hard to find either with a little searching.
It's a really large file though so I don't want to bog down the site by directly posting it here. Anyone who wants it, let me know and I will PM it out to whoever asks for it.
Edit: I forgot to say, no, I don't know where the working link is if there even is one anymore. I tried, but couldn't find it when I had looked for it.
-Dylan
Re: JBM Small Arms Ballistics working link?
Thanks Dylan, that should be a good starting point. PM sent with contact info.
Thanks Dylan, that should be a good starting point. PM sent with contact info.
Re: JBM Small Arms Ballistics working link?
I've played with JBM and Exbal a lot pertaining to subsonic rimfire rounds, and it's not a straight forward problem to devise a solution for. I've tried using the chrono'd velocities and published BC's for rimfire rounds to get solutions and rarely is it really anywhere what I would call acceptably close. In order to get my exbal to match up to real world data with Eley match, I had to use a muzzle velocity of 1025 with a BC of .100 to get it to match up with 100, and 142 yard drop information with real time atmospheric conditions.
Now with Exbal and Wolf MT, i'm using 988fps and .130G1 to get my drops, but it's only working to 200, it was short by quite a bit at 300 on this latest outing which was about 30 degrees cooler than my October outing.
Sometime i'm going to shoot all rounds over a chrono at each range recording drop data. Going to get drop information for 100, 150, 175, 200, and 250. I've shot 300 in the past, however it seems that now my scope suddenly doesn't want to adjust past ~52moa up, perhaps it didn't do it back then, and I just never noticed. Last time I was pinging a 12" target at 300 yards with 61moa.
300 yards is fun to say you hit a target that far, but when it's a full IPSC target (like this most recent outing), it's really nothing to brag about. I can get decent, rather usable groups at 200 yards which could get me some ground squirrel kills as long as I can range it perfectly, and hit some rather small targets that some struggle to hit with even centerfire rifles. All you that shoot further, have at it, for me, 200 in some wind is as much challenge as I need.
Branden
I've played with JBM and Exbal a lot pertaining to subsonic rimfire rounds, and it's not a straight forward problem to devise a solution for. I've tried using the chrono'd velocities and published BC's for rimfire rounds to get solutions and rarely is it really anywhere what I would call acceptably close. In order to get my exbal to match up to real world data with Eley match, I had to use a muzzle velocity of 1025 with a BC of .100 to get it to match up with 100, and 142 yard drop information with real time atmospheric conditions.
Now with Exbal and Wolf MT, i'm using 988fps and .130G1 to get my drops, but it's only working to 200, it was short by quite a bit at 300 on this latest outing which was about 30 degrees cooler than my October outing.
Sometime i'm going to shoot all rounds over a chrono at each range recording drop data. Going to get drop information for 100, 150, 175, 200, and 250. I've shot 300 in the past, however it seems that now my scope suddenly doesn't want to adjust past ~52moa up, perhaps it didn't do it back then, and I just never noticed. Last time I was pinging a 12" target at 300 yards with 61moa.
300 yards is fun to say you hit a target that far, but when it's a full IPSC target (like this most recent outing), it's really nothing to brag about. I can get decent, rather usable groups at 200 yards which could get me some ground squirrel kills as long as I can range it perfectly, and hit some rather small targets that some struggle to hit with even centerfire rifles. All you that shoot further, have at it, for me, 200 in some wind is as much challenge as I need.
Branden
Re: JBM Small Arms Ballistics working link?
Thank you, my desire to look at JBM for small bore came from shooting IBS rimfire targets yesterday and the wind blowing my shots around. Had to set windage over more than a MOA and a half at 50 yards to get close to center circles.
I had the dope for my range but didn't have any windage values on the current data cards. Playing around I can almost get JBM to match using a ballistic coefficient of .130 and muzzle speed of 1100. I'm going to get a chrono and take the same measurements you talked about DR for both ranges I shoot 22 at.
Thank you, my desire to look at JBM for small bore came from shooting IBS rimfire targets yesterday and the wind blowing my shots around. Had to set windage over more than a MOA and a half at 50 yards to get close to center circles.
I had the dope for my range but didn't have any windage values on the current data cards. Playing around I can almost get JBM to match using a ballistic coefficient of .130 and muzzle speed of 1100. I'm going to get a chrono and take the same measurements you talked about DR for both ranges I shoot 22 at.
Similar threads
