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These drops in inches are straight out of "Ultimate sniper" By major John L. Plaster. Regarding M-118, 7.62mm NATO Match boat-tail Ball 173 Gr.
[/ QUOTE ]I know these numbers aren't right. Having worn out 4 barrels in 7.62mm NATO converted M1 Garands and a lot of the ammo was LC M118 Match (M2 173-gr. bullet), my zeros (I've always remembered them) were as follows at sea level for the M1NM rear sight having a bit more than 1 MOA per elevation click; one can calculate the bullet drop at each range from this data:
200 yards, 5 clicks up from the bottom (front post height changed to do this; 200 yard drop = 10 inches).
300 yards, 3 up from 200 yards, up 8 total.
600 yards, 12 up from 300 yards, up 20 total.
800 yards, 10 up from 600 yards, up 30 total.
900 yards, 6 up from 800 yards, up 36 total.
1000 yards, 7 up from 900 yards, up 43 total (that's about 440 inches of drop).
I'll run my Sierra Bullets software and see what happens for their 30 caliber 175-gr. HPMK.
Plasters book data is just flat BAD!!!! I wonder sometimes if it was done intentionally. Bart, were those comeups from a 20"gasgun?
A friend's Knight SR25Mk11 does 2544fps with the 175gr, and its 63fps faster with the supressor mounted. We have found that his drop data come very close to the standard Leupold cam for 168gr ammo from 24" barrels. You may want to give that a try. Shawn probably has access to far more stuff than me, so i he has a different average velocities for more than 1 rifle, please disregaurd my info.
I should have mentioned. This is NOT M118LR which is a 175gr MK. It is M118, It is Lake City.It has a very tiny hollow tip but is classified as ball, I just found the data, it is 173 grain
If someone has a gas gun ar10 or sr25 with that ammo it would be great to get actual velocities.
Thanks everyone for the help. I do not trust the "sniper" boards as much for data.
Carlock, I saw super Dave in Jordan on my way through. He is living large.
Y'all save some rockchucks for me [img]/ubbthreads/images/graemlins/grin.gif[/img]
Once upon a time I lived and breathed the technical data in that book... then I started putting one and one together... read through the mildot data a few times and something funny strikes... He makes no mention of the differances between army and marines mildot reticles, and uses the math indescriminately too!!!!
And the list goes on and on...
Now my plaster book is full of notes in the margins on what is wrong [img]/ubbthreads/images/graemlins/smile.gif[/img]
I have all of your data. Just let me know where to send it. I shot a 20" DPMS with the LC M118 yesterday. Average velocity 2558 fps, also shot some through a 24" custom Rem 700 that belonged to a local customer average velocity 2624 fps. The bullet you talk about is the 173 version and after some reserch I find the BC is just .004 less than the SMK. I have all the data you need I just need a location to send it to. There is to much to post here. I also included 10 mph wind and 1 mph moving target lead.
About Plaster - My understanding from some of the been there, destroyed it and got the ribbon guys I know of the Plaster / Vietnam era, is that Plaster was a good SOG guy but never spend any amount of time as a sniper he just collected info and wrote the book. I was not there but have gotten this same story from a number of people I really trust.
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Bart, were those comeups from a 20"gas gun?
[/ QUOTE ]No; standard 24-inch 7.62 NATO Garand barrel with 1:12 twist (I know, .30-06 ones had 1:10 twist but these were made to US Navy specs). They were custom made by Springfield Armory, MA but were tight; .2995" bore, .3076" groove, broach rifled and extremely uniform dimensions from throat to muzzle. They shot the same M118 ammo about 75 fps faster than the normal, larger bore & groove diameters standard service barrels had. With good handloads, the best of them would stay inside 4 inches at 600 yards; not too shabby for a gas gun's ability to have all those moving parts (op rod and all) back into battery exactly the same for each shot - and a whippy barrel to boot!
That's gonna be the big error factor in what this guy wants. Without chronographing ammo from the acutal barrels, the muzzle velocity I use with the software may be 50 fps or more off from what they get. To say nothing of the powder temperature when the round's fired causing velocity changes. And different lots have different muzzle velocities. Whatever I come up with will be a SWAP; Scientific Wild Ass Prediction.