SniperCentral

[shelbuilt]

this is probably a premature question followed by a general question i should know just being apart of this site sorry for the iqnorance.

i have only loaded 20 rounds my whole time i have read the 49thedition lyman book and and the cabelas sponored 308 book on reloading

i am using sierra match king 175 and winn 760 cci 200 primers with win once fired brass rcbs fb resizing die. and a lee seating die.

i just mounted an eagle eye 6-24-50 scope and love it superior to my bushnell elite in all aspects with a healthy amount of eye relief.

my rifle has a 4.5 trigger and 1and 9 twist springfield heavy barrel

my question is with everything i am doing and have done. is 3/4"at 100yds
(on a warm barrel) what i should be shooting in the prone position off a soft barrel rest

i have two groups on just under 3/4 and the other just over

and what is the term moa stand for and mean? i have heard sub moa rifles and not quite figured it out? thanks sorry for the long drawn out general post. thank you in advance for your response
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m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[04nnj57111]

You sure it's not 1x10 twist?

[MitchAlsup]

MoA stands for minute of arc. Without going through all the math, it ends up that 1 minute or arc is just over 1 inch at 100 yards. 1.047

http://en.wikipedia.org/wiki/Minute_of_arc

1 inch group at 100 yards is the standard accuracy requirement for a sniper rifle and if the shooter can be trained properly* a rifle of this accuracy level is deadly to human sized targets as far away as 1000 yards.

(*) properly includes, aim, wind reading, ballistics, record keeping, compensations for atmospheric effects, and more.

[shelbuilt]

thank you for the definition. it is very helpful

i looked at the barrel just last night and it is a 1 and 9. i also assumed it was a 1 and 10 a few months back until i took it apart and cleaned it and realized it said 1 and 9? i thought that to be a little strange i will look at it closer on the next cleaning maybe i am not reading it right or something?
i will try to get the name off the barrel and post pics.

update i shot just under 1 moa today at 175 yrds. reason the odd yardage is because it is flat and comfortable to set up under the shade and lay down to shoot.

but with my off the shelf win 180g sp (i bear hunt with) i shot a measured od .89 3 shotand .77 3 shot. on a cold barrel only 6 shots total. before i went hunting only different is i changed to high magnification scope but still shooting at 10X and i upgraded to alot better mounts shoting my sec batch of handloaded 175 bthp with win 760 powder i shot 1 moa today.

can anyone give me some insight. i know i need to refine my loading i have only loaded 60 rounds total. but is the wide spread grouping anywhere from .75 to 1.5 in the acceptable range for my m1a sorry for the long post any input it thanked
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m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[oneeyedmac]

Well onr MOA at 175 yards is 1.837". So if you had an extreme spread of .89" and we subtract .308 (the width of a .308 bullet) it's .582" so that's .31MOA. If the extreme spread was .77 at 175 yards and we subtract .308 it's .462 which is .25 MOA. That's pretty darn good for any gun but especially a gas gun.

Someone correct me if I'm wrong.
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www.excorioprecisionarms.com
Bubba's Hunt Shop

[shelbuilt]

i am a little confused by your measurement post as far as why you did the math is there any where that i can see a educated break down? or if you would like to elaborate i would greatly appreciate it.

i believe i figure out my wide spread on my sec batch of hand loads i forgot the step on trimming the case. and learned today that is one of the most important parts on a m1a!?.... lol i guess i learned the hardway.just glad no damage was done to my rifle.
_________________
m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[JCinPA]

I'm not sure what part of the math you are unsure about, so I'll cover both areas I can think of that may be causing confusion. The first is simply how to measure group size. Below should clear that up.



The second is how MOA relates to group size at distance. One MOA subtends an angle that would measure approximately 1 inch at 100 yards. It is a little more than that, but 1 inch is close enough. As you move out, add 1 inch for every 100 yards. For example at 200 yards one MOA translates into a group size of 2 inches, at 300 yards it is 3 inches.

Precision shooters prefer to talk about MOA because it describes accuracy regardless of distance. If I say I shot a 1.75 inch group at 200 yards and a friend shot a 2.25 inch group at 300 yards, which was the 'tighter' group?

Well, obviously the 1.75 inch measurement is smaller than the 2.25 inch measurement. However, at 200 yards, that 1.75 inch group represents 0.88 MOA. The math is 1.75" divided by 2.0" (an MOA at 200 yards).

The 2.25 inch group at 300 yards represents 0.75 MOA, so it is a tighter group size (2.25" divided by 3.0"). Using MOA enables shooters to compare accuracy at distance using a standard unit of measurement that does not change with distance.

To be sure, the difficulty of shooting smaller groups increases with distance. It's harder to see the target clearly, movement by the shooter is magnified, doping windage becomes an issue. But the MOA standard describes a mechanical measure of pure accuracy that one can compare at any distance.

Finally, I'm using the 1 inch per 100 yards estimate. Assuming MitchAlsup's number is correct (and I assume it is), what Oneeyedmac was saying was an MOA at 175 yards would equate to 1.047 X 1.75 = 1.83 inches, approximately.

That help?? Although I will calculate more decimal places, I never record more than two places. Measurements are never more precise than that, and it's good enough for comparison purposes. That's why I don't bother with Mitch's more precise number . . . 5/100" won't add up to an extra inch in group size until you hit 2,000 yards! If you get the relationship between MOA and inches/yard, use 1 inch per hundred yards and you should be good to go.

Now, using meters . . . nah, inches is easier in this case. If you are a math geek, see this. . .

http://riflestocks.tripod.com/moa.html


Edit: here is it for meters

[becks]

I cant believe I missed this, do you have any photos of the rifle?
Hows it grouping for ya?
_________________
#2 Infidel
Jeff Dorr...Gone but not forgotten

Next builds:
"Black and scary assault sniper rifle"
"machine sniper pistols that spray bullets from clips"...Thanks CNN,NBC & CBS

[shelbuilt]

wow thank you jancinpa it really clears it up all my measurement have been outside to outside. makes me feel alil better with my accuracy

the rifle with factory ammo win 180grn sp at a measured 100 yards was grouping a more consistant .75 moa some smaller at times but hardley ever bigger

(this is extreme measure of 1")

but i loaded correctly 6 rounds of win. brass, 175 smk, win. 760 45gr, cci 200 primers. oal 2.815. col was 2.010

and fired a three shot goup of extreme. measure. .73
and the next thre shot group ext. meas. was .60

measured at the widest point

so it is grouping .73-.308= .43 moa
.60-.308= .30 moa

i am no marksman yet i can just as easy shoot a good group and then fly a few groups before i get a good one. but these two groups were back to back.

i posted to see if my rifle was not as accurate as it should be and after reading. moa (if i am right on my math and the center to center measure) of my rifle is more then accurate for the major part of m1a owners.

not sure i a mentioned that my rifle is a standard with a match barrel with the trigger and gas system and guide rod all changed out by a smith (and possibly more un noticed yet?)before i got the gun minus the sei piston i put in it. i trade my old race quad for this rifle i am very very pleased. the close to 14000 into my bike i would never think of dropping and estimated 3500 into my rifle with everything done until i owned one. i love my m1a, but i am still on the search for a bolt gun thinking a sako m995 rebarrelled in 33/378 the things dreams are made of!
_________________
m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[ekaphoto]

FYI to make matters simple. 1 MOA= 1 in at 100 yards, 2 in at 200 yards, 3 in at 300 yards etc etc. So a 1 inch group at 200 yards would be 1/2 moa.
_________________
John

1.Humans are more important than Hardware.

2.Quality is better than Quantity.

3.Special Operations Forces cannot be mass produced.

4.Competent Special Operations Forces cannot be created after emergencies occur.

[shelbuilt]

this is my rifle pics as requested

[/img]
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m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[becks]

What a beauty!
_________________
#2 Infidel
Jeff Dorr...Gone but not forgotten

Next builds:
"Black and scary assault sniper rifle"
"machine sniper pistols that spray bullets from clips"...Thanks CNN,NBC & CBS

[shelbuilt]

thank you for the completement i have the rifle willed to two people if i die before them i said they could fit over it a retired vet and proclaimed cowboy. then a good friend that should have been a marine.

and to think when i first acquired the rifle i thought it was funny looking...
huh guess i got assed with that asssumption now!
_________________
m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[shelbuilt]

i like pictures of rifle dont know how many would want to look at mine here is a picture of my rifle with the new bipod




_________________
m1a nm smith mount and cheek rise 6x24-50
rem 700 LE CQT 4 rd mag 8x32-50
savage fv .17 6-18x50
win .243 mod 70 3x9-50 elite ff mod 70 fl stock
henry goldboy 22lr
ruger hawkeye .338 federalaction and trigger.

[becks]

Would you take my girlfriend in trade for the rifle?
_________________
#2 Infidel
Jeff Dorr...Gone but not forgotten

Next builds:
"Black and scary assault sniper rifle"
"machine sniper pistols that spray bullets from clips"...Thanks CNN,NBC & CBS