Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login

Site Notices
Posted: 6/23/2016 10:16:53 PM EDT
Long story short. Will be headed out shortly to a long distance shooting class. Would like to purchase FGMM 175 for the class.

Will be using a Savage model 10 with a 20" barrel, 1:10 twist. Unfortunately, don't have the time to measure muzzle velocity to develop ballistic drop table.

I looked on Federal site, but they don't identify what barrel length they used to get their advertised 2600 fps.

Does anyone here have measured MV data using a 20" barrel?

Thanks in advance.
Link Posted: 6/23/2016 10:55:50 PM EDT
[Last Edit: 6/23/2016 11:00:05 PM EDT by md7989]
I'm going to guess you're around the 2530-2550 fps range:

http://www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/

That might get you in the ballpark. Hopefully others will chime in...but why no time to get dope dialed in? Most classes allow shots in a short time period before a class to build a dope card (heck, most classes even teach the building of the dope card itself)

Another link to glocktalk shows a guy with:

Remington 700 20" barrel 11.25" twist 5R rifling:
Federal GMM 175 gr 2543 fps Average with SD=9

Sorry I don't have any measured data (don't shoot 308)
Link Posted: 6/23/2016 11:43:51 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By md7989:
I'm going to guess you're around the 2530-2550 fps range:

http://www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/

That might get you in the ballpark. Hopefully others will chime in...but why no time to get dope dialed in? Most classes allow shots in a short time period before a class to build a dope card (heck, most classes even teach the building of the dope card itself)

Another link to glocktalk shows a guy with:

Remington 700 20" barrel 11.25" twist 5R rifling:
Federal GMM 175 gr 2543 fps Average with SD=9

Sorry I don't have any measured data (don't shoot 308)
View Quote


Yea, I guess I am being a little anal. I would like to use JBM ballistics before the class to make a predicted dope sheet to then compare to actual shooting results.

I feel the timing is short because I must order FGMM online. None available locally.

Since I made the original post, I found a site that measured FGMM 168 grain in a 20" barrel. Their data showed a 84 fps drop from Federal published data. Sooooo, if I make the assumption that Federal used the same rifle and barrel length when developing their 168 AND 175 data, then maybe, just maybe, the 175 gr data will also experience an approximate 84 fps drop. If so, that would indicate a MV of (2600 - 84) = 2516 fps out of a 20" barrel.

I ran JBM calculator using your high estimate of 2550 and my estimate of 2516 fps. Both indicate staying supersonic past 1100 yards.

Thanks for your help.
Link Posted: 6/24/2016 7:28:14 AM EDT
I chrono'd my buddy's Rem 700 20" barrel, 1-12" twist shooting 175 gr Fed Gold Match.

2561
2564
2550
2664
2614

2576
2592
2585
2584

There was something really odd going on with the 2600+ readings.
Link Posted: 6/24/2016 8:14:14 AM EDT
No problem. Where is the match going to be at and what is the weather forecast for then? Depending on temp, it might add or subtract a few mils off your dope, since we know how things react to temps in terms of velocity. Always hard to say without getting velocity data the day of the match and onsite. But I agree, playing around in JBM ahead of time is always a good idea
Link Posted: 6/24/2016 11:16:36 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Ironmaker:
I chrono'd my buddy's Rem 700 20" barrel, 1-12" twist shooting 175 gr Fed Gold Match.

2561
2564
2550
2664
2614

2576
2592
2585
2584

There was something really odd going on with the 2600+ readings.
View Quote


Thank you. That is just what I was looking for. I think I'll exclude the two 2600+ fliers. I've seen similar questionable data with my chrono.

An average of the remaining values show an average of 2573. Better than I expected. That's all good news

Thanks again
Top Top