This is a discussion on Handgun Muzzle Velocity vs. Barrel Length within the Handguns forums, part of the Gun Forum category; Ladies & Gentlemen,
Can anyone please tell me how much velocity can be gained/lost per inch of barrel? I want to use this info to ...
Ladies & Gentlemen,
Can anyone please tell me how much velocity can be gained/lost per inch of barrel? I want to use this info to calculate true external ballistics for each sidearm/load combo that I own. Thank you to all in advance!
I wish there was some easy way of doing just what you're talking about - I guess there is, but it's not cheap. I'm not aware of any easily accessed databases that contain the info you're looking for - for every type of handgun and ammo combination. Of course, some of the "Old Salts" around here may know where there may very well be databases that I don't know about .
The BEST way I know of to calculate the external ballistics with any precision is to use a chronograph, then run the results through some ballistics software using the information on the caliber, bullet shape, BC and SD, elevation, ambient air temperature, humidity, wind, and all that stuff to calculate where your bullet will be at any given range, for a given sight zero.
You can come fairly close be using the tables that usually come with most loading manuals, provided you use the correct bullet weight/shape.
Since we're talking about handgun ballistics here, variance may not be as critical as it would be if we were talking about a long-distance rifle shooting.
If it was me (and I've done this many times), I'd just chronograph the loads, using your handgun and "run the numbers". That way, you'll know for sure what the velocities and POI are at any given range. Most of the ballistics software (I use Sierra's Infinity software) will even print you out a nice graph for your gun/load combo when you plug in all the info.
For pistols you lose or gain about a 100 fps for each inch up to about 10 inches using a balistic chart for the load in question. Handguns in pistol caliber start to lose velocity after that in long barrels, not enough powder.
Eg 9mm in a 4,25 incher is loud and fast, stick it in a standard uzi 10 inch and its still loud and fast, put it in a 16 inch uzi barrel and it is whisper quiet.
Duckbuck & Dogrobber, Thank you both I guess that I'll have to break down and buy a chronograph when I can afford one The basic data that I have is from Federal Cartridge Co. The only problem is, they use a 4" test barrel for the .40 S&W. My quest is this: I shoot/carry the 155 gr. Hydra-Shok in both my Glock 35 and Glock 27. I want to figure out the basic external ballistics for this load from each of these pistols. From the info that you gents have provided, I should be able to acheive this until I can get a chrono Thanks again!
Glocks usually get a bit higher velocity figures because of the polygonal rifling. In my experience (however limited that might be) I only ever lost about 50-60 fps per inch....and my Glocks were almost the same as my longer 1911 clones. FWIW, the ProChrono can be had for about a c-note and has been good property for me.
Thanks Duck, that is what I was looking for. My department is looking into going to a department issued weapon. The Glock 22 and 23 are at the top of the list. Since I already purchased all the .40 cal ammo for the year, I was looking for the data....