M3A offset for 500m zero

KSC · 06-29-2007, 10:34

I recently obtained an M14 w/M3A to take care of some neighborhood pests we've been dealing with. I got some great holdoffs for a 500m point of aim/point of impact, but, given my living conditions I don't have a 500m range available aside from the two-way variety.

So my question(which I, of course forgot to ask the B4s), using M80 ball(I know), what would my offset be on a 25m short stop or can I obtain close enough results using something 50m or shorter?

I'm not going to be using it for HVT hits or anything like that. I'm pretty confident in my range estimation, which I do using mil-relation. Since most of the times I've ever needed one it's been in the sub 400m range, I'm confident that the M80 rounds will be sufficient.

82ndtrooper · 06-29-2007, 11:27

Are you referring the the McMillon M3A stock system ?

**The Reaper** · 06-29-2007, 11:42

I do not advocate pest control with a 7.62 unless they are over 200 lbs. and in a rural setting.

You may want to chat with a local LE member and see how they will react to a report that someone is firing a "big gun" near their home.

If you are currently deployed and are using this for sanctioned two-legged pest control, disregard and carry on.

TR

Gene Econ · 06-29-2007, 17:28

Quote:

Originally Posted by KSC

I recently obtained an M14 w/M3A to take care of some neighborhood pests we've been dealing with. I got some great holdoffs for a 500m point of aim/point of impact, but, given my living conditions I don't have a 500m range available aside from the two-way variety. So my question(which I, of course forgot to ask the B4s), using M80 ball(I know), what would my offset be on a 25m short stop or can I obtain close enough results using something 50m or shorter? I'm not going to be using it for HVT hits or anything like that. I'm pretty confident in my range estimation, which I do using mil-relation. Since most of the times I've ever needed one it's been in the sub 400m range, I'm confident that the M80 rounds will be sufficient.

KSC:

Well, seeing as you are blasting M-80 from what is probably a service grade M-14 whose barrel has probably been trashed already, zero your M-3A optic point of aim / impact at 25 meters using 300 on the optic if the BDC is calibrated for M-118. I am betting it will be within 1 1/2 minute up or down at 500. This isn't linear.

You will also find that M-80 doesn't go 2800 fps from an M-14. Maybe 2750 but most likely between 2700 and 2750. So things can get problematic but you will find very little difference in trajectories of M-80 and M-118 to 500 M anyway so due to all of these small problems, I still predict you will be within + - 1 1/2 minutes at 500.

Gene

KSC · 07-01-2007, 06:29

82nd- Nah, the M3A mildot scope.

Reaper, sorry, I was talking about the IED emplacing, pot shot taking pests.

Gene- 1.5 sounds good to me. 8 inch strike area at 500m gives me about 5 inches on either side to play with. I like to range Iraqis as having 18 inch shoulders over the 20 inch ivans. Probably better off calling it 17.

Gene Econ · 07-01-2007, 19:06

Quote:

Originally Posted by KSC

82nd- Nah, the M3A mildot scope. Reaper, sorry, I was talking about the IED emplacing, pot shot taking pests. Gene- 1.5 sounds good to me. 8 inch strike area at 500m gives me about 5 inches on either side to play with. I like to range Iraqis as having 18 inch shoulders over the 20 inch ivans. Probably better off calling it 17.

KSC:

Sometimes you find a BDC for M-80 in the deployment kit if you have one.

What I gave you is sufficient for your spotter to easily read your trace at 500 so your best bet is to find something that is 500M and after you zero at short range, take a couple of shots at 500 with good calls and work with your spotter to get a better zero.

Short range zeros are not a good idea to trust for life or death situations.

Not sure if you are using a service grade or Supermatch. Do you know?

Gene

KSC · 07-02-2007, 11:34

Nah, we're using delinked M80 ball. There's no M118 special ball or long range available right now- sad, deffinetly sad.

Gene Econ · 07-02-2007, 21:33

Quote:

Originally Posted by KSC

Nah, we're using delinked M80 ball. There's no M118 special ball or long range available right now- sad, deffinetly sad.

KSC:

Not what I 'axed'. Let me 'axe' you 'pacifically'. Are you shooting rack grade or Supermatch M-14's?

You would be surprised at how well M-80 can shoot in a Supermatch.

Gene

Gene Econ · 07-02-2007, 21:47

Quote:

Originally Posted by KSC

Nah, we're using delinked M80 ball. There's no M118 special ball or long range available right now- sad, deffinetly sad.

KSC:

Oh yes -- sorry -- but 'Nah' isn't polite. My name is Gene. Not 'Nah'.

If I ask a question, I always say 'thank you'. It pays sometime and somewhere.

I am polite to my fellow professionals here, be they Servicemen, Servicewomen, LEA, or Civilians. I start my posts to them with their names -- not "Nah".

So, be a professional. You have the time -- let me assure you. LR1947 and I have shot more White Box M-118 Match out of M-14's than you have shot M-80. In fact, we have shot more damn M-80, 852, 118 SB, and 118 LR out of about every generation of M-14 known to man than you have.

So be polite -- you have the time.

Thank you

Gene