Mosin Nagat Barrel length vs Velocity

[poolingmyignorance 2,191]

I've been working on a mosin and was planing to cut and recrown the barrel as it's counter bored, and so have been trying to determine an acceptable lenght. After meandering through countless thread after thread on various forums, and endless " well it depends on what ya wanna use ya rifle for" answers and hersay, I found this study performed by Brandon Luis Clark of University of South Florida. It's straight forward scientific method to establish a data curve.

http://honors.usf.ed...s/U82488180.pdf

 

So I'd like to add some of his data to this post for eaiser viewing and quicker reference. Again all info and images belong to Brando Luis Clark .

Meat and bones of the study concluded this:

"After compilation of the velocity data, the average velocity of each barrel length iteration was

extracted and plotted in relation to the barrel length. From here a linear curve was fit onto the

data points, yielding a coefficient of determination (R

2 Value) of over 99 percent. The

significance of this value may be expressed in Layman’s terms as “The Linear Curve fit onto the

Velocity vs. Barrel Length data may accurately describe the data points within 99 % accuracy”

or even further simplified as “The Velocity vs. Barrel Length data is inherently linear”. The

average velocity difference per inch of barrel length (slope of the line) was 25.658 (Ft/Sec), or

51.316 (Ft/Sec) per barrel length iteration (2 inch cut)."

It was also noted that another study determined that sound volume increased 1db per 1" of barrel length reduced.

[theorangeplanet 968]

Funny you should post this. I've been planning on getting a couple of mosins and making a scout rifle build for my brother and I as a little project, so this topic has been a point of research for me this week with this paper being a invaluable source of solid info. For my plans, about 22-23 inches will do, I believe. SVDs are around that, right? Next step for me is settling on a scope mount... looks like getting dovetail rings or a dovetail to weaver mount is more sturdy that most of the aftermarket mounts out there.

[thebuns1 4,323]

pretty interesting info pool. how short are you going to go with it? i had a buddy of mine do something similar with his, then he found out that he could have just bought an m38.

 

i like my mosins to be full size, but wouldnt mind pickin up an m38, either.

[G O B 3,516]

My M-38 is one of my favorites. Goes to the range most every time, if everything else FUBAR's she puts the smile back on Grumpy's face!

[poolingmyignorance 2,191]

pretty interesting info pool. how short are you going to go with it? i had a buddy of mine do something similar with his, then he found out that he could have just bought an m38.

 

i like my mosins to be full size, but wouldnt mind pickin up an m38, either.

Well its counter bored back 1.477" so an even 2" should allow it to fit in a standard rifle hard case. Im building this mostly for range work. I know qn M38 would save time,but i enjoy building to my own specs. On a down note Ill have to buy a crowning tool as the steady rest on my lathe will only go down to 1.5" dia. Oh well..

[bulldog_shotgun 47]

manson reamers make really nice crowning tools.

[thebuns1 4,323]

pretty interesting info pool. how short are you going to go with it? i had a buddy of mine do something similar with his, then he found out that he could have just bought an m38.

 

i like my mosins to be full size, but wouldnt mind pickin up an m38, either.

Well its counter bored back 1.477" so an even 2" should allow it to fit in a standard rifle hard case. Im building this mostly for range work. I know qn M38 would save time,but i enjoy building to my own specs. On a down note Ill have to buy a crowning tool as the steady rest on my lathe will only go down to 1.5" dia. Oh well..

 

i like doing shit myself as well. its the only way to really learn IMO. are you going to move your front sight? keep us posted on the progress.

[poolingmyignorance 2,191]

Plan is to move the font sight back after cut and recrown, turn down the bolt handle so it will clear a scope. And add a mount, either drilled and tapped to the side, or tapped blocks welded to the top of the receiver, to affix a pic rail. Not really sure how I feel about using the rear sight block as a scope mount. I've heard mixed results. If that does become the location I use, I'll weld the rail on to it so it won't have any play.

[thebuns1 4,323]

ive read mixed reviews on using the rear sight base as a mount as well. should be a fun project none the less.

[poolingmyignorance 2,191]

I think I'd like to keep this thread pretty clean, and leave it just to the technical info. So I'll be updating on my orginal thread, that I started for my Mosin. : http://forum.saiga-12.com/index.php?/topic/77576-ive-got-wood/page__hl__%2BI%26%2339%3Bve+%2Bgot+%2Bwood.

All my progress on this particular rifle will be included on this thread. Thanks.