Fieldcraft Fieldcraft ?

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Guest

Guest
Your target is setting in a Russian BPM1 an presents his self 2-3 times an hr out of the commanders hatch right behind the 14.5mm auto cannon. You can only see him from the belt buckle up, the armor is setting flat on the ground but at a 35* angle to you. Your LRF is not working correctly, but the armor height subtends 6.42 MOA, in your scopes retical.
What is the distance to target?
Will the 300wm your carrying reach the target.
Would you shoot from that distance?
 

Sumpter Steve

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Re: Fieldcraft ?

- but the armor height subtends 6.42 MOA.

What does that mean? Dumb it down for me please and I'll try to figure it out. I'm not the sharpest tool in the shed. LOL.
 
G

Guest

Guest
Re: Fieldcraft ?

Sorry, I should have said your scope has a MOA retical, an the armor height (top to ground)is subtending 6.42 moa.
 

Sumpter Steve

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Re: Fieldcraft ?

Height of a BPM = 57.9"

My (hillbilly) math:
57.9 / 6.42 x 100 = 901 yards.

Man from the waist up is about 30" tall.

Yes, the rifle would make the shot.
Yes, if everything was GTG I would take the shot.

How bad did I do?
 
G

Guest

Guest
Re: Fieldcraft ?

Your number for the BPM1's height is incorrect.

If your useing MOA to range, it's
Target in inchs/MOA subtention X 100 = range to target.
 

Lindy

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Re: Fieldcraft ?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If your useing MOA to range, it's
Target in inchs/MOA subtention X 100 = range to target.</div></div>

Umm, no. If you're using MOA to range, the formula is:

distance(yards) = (size of target inches * 95.5)/image size in MOA

The 95.5 would be 100 if the reticle were in inches per hundred yards (IPHY).

See:

http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Ranging/
 
G

Guest

Guest
Re: Fieldcraft ?

Your right as my stuff is in IPHY, but I always say MOA, my bad.

But, lets keep the answer in true moa, not IPHY. Or it could be given in both, just to show the yardage difference?


 

Lindy

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Re: Fieldcraft ?

I'm assuming that you mean a BMP-1.

The web site http://warfare.ru/?lang=&compare=true&linkid2=2071&linkid=2304&catid=245

gives the height of the BMP-1 as 1.924 meters, which is about 75.75 inches.

Unfortunately, the foreshortening effect of that 35 degree angle introduces enough uncertainly into the measurement of the target that I wouldn't trust the measurement at that distance. I'd pass on the shot, and get on the radio to the tactical air control center.
 
G

Guest

Guest
Re: Fieldcraft ?

My old data for the BMP1 shows a combat stance (height)of 85.5" from top of the commanders closed turret to ground. Length = 265.25" an Width of 115.75"

I choose a 35* angle to see if anyone would use anything other than the height as if it's setting flat, the height would not change.

I too would pass on the shot as I get 1332yds,... too many errors to stack up on that shot, an the 14.5mm can reach. Better to pass on a direct, an think indirect, or Tac Air.
 
G

Guest

Guest
Re: Fieldcraft ?

US XM21(in the wrong hands) subtending 7.71 (all in IPHY)

US 1911A1 (Hammer down) @ 5.59

Russian Makarov, hammer cocked, @ 3.25

Russian SVD Tiger @ 6.79

Russian SV-98 @ 4.88
 
G

Guest

Guest
Re: Fieldcraft ?

Or this one, she is subtending 5.11 IPHY

pk_original.jpg
 

doc76251

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Re: Fieldcraft ?

MK-19 and call all your friends that have guns.

Specter on standby just in case you realy screw up or that lump of grass at 850 isn't a lump of grass
laugh.gif


Cheers,

Doc

Oh yeah, shoot the wimmin's first
 

LS6TT

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Re: Fieldcraft ?

i agree on air strike. they dont roll alone and id be f'ed after i took the shot.

and i came up with 840 (give or take) yds so i need to redo the math
 
G

Guest

Guest
Re: Fieldcraft ?

Last Photo was a PKM,(7.62x54R) which is 46.9" in length,... 46.9/5.11 x 100 = 917 yds.

Try this one at subtention of 6.37 IPHY

SV98.jpg


Or this one subtending 3.76

1194048059_3.jpg
 

Pete E

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Re: Fieldcraft ?

For very long distance shots (say +500m with a 7.62 Nato) I'm not convinced that subtention method works reliably enough in the field as very often the target is not "square on" nor is it the same elevation..
 
G

Guest

Guest
Re: Fieldcraft ?

That is correct, but not knowing how is a road to nowhere. At least if one can subtend fairly well, they should be able to get to a FP distance required for their round to fall within their error range.

The thing I see in this thread an elsewhere, is everyone wants to rely on the radio,...or outside help alot. Thats the smart move at times, but what happens if your commo is a no go, or the other end is out of help? One needs to be able to try an complete the task, with whats at hand. Giving up is the easy way out.

A knife fight is want changed many battles and the over all out come, many times. Lossing that ability would be a huge mistake, one this country has made more than a few times in the past.
 

Lindy

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Re: Fieldcraft ?

Clint Smith once said about the tactics involved in house-clearing by a single person, "We study this not because we want to do it, but because we might <span style="font-style: italic">have</span> to."

Knowing how is better than not knowing.

The technique of last resort is almost always better than a wild guess.
 
G

Guest

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Re: Fieldcraft ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">Knowing how is better than not knowing.
The technique of last resort is almost always better than a wild guess.</div></div>

Thats 100% correct.
I wonder why so many on here have a ranging retical in the first place.
crazy.gif

I'm odd I know but when I buy a tool I assume it's my job to learn how to use it. Otherwise to me it's money spent just to,....
 

Pete E

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Re: Fieldcraft ?

I don't disagree thats its better than a guess, but unless people are realistic about their own personal effectiveness using the system, you are going to get misses anyway..

Have you guys done the math and worked out at what point the probably error in subtention method means the round is likely to miss say a 18"x10" upper torso target?

Its along time since I did this properly, but as I recall the crux of the problem is that as the range increases, the more likes it is to be miscalulated, but the longer distance, the more critical an accurate range estimate is to hitting the target.

I used to be a driver of a Fox, a small armoured car that was used for medium range recce...

Given my earlier years in the infantry, I was very at home map reading, and I would often piss the gunner and the commander off when they were having the "How far?" debate..

They would be doing the same sort of thing as you guys ie using the mils graduated reticules in the vehicle's optical sights, but I would give them a far more accurate and quicker answer by measuring it off the map!
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Regards,

Peter

 

Lindy

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Re: Fieldcraft ?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Have you guys done the math and worked out at what point the probably error in subtention method means the round is likely to miss say a 18"x10" upper torso target?</div></div>

Yes - it's a good exercise. And if you look at my second response in this thread, I wrote that I'd pass on that shot due to uncertainties in the range estimation.

But beyond about 700 yards with a .308, a map estimate isn't likely to be good enough either.

At 1000 yards with a standard .308 load, a 20 yard range estimation error results in a miss in a 20" target, and you're not going to get within that error range with a map except by luck.
 

Pete E

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Re: Fieldcraft ?

Lindy,

The weapon in question was the vehicles 30mm RADON cannon and the distances being debated were betwen 1km and 3km...the gunners considered anything up to a 1km as a dead cert...

I never did my gunners course but would listen to the endless debates over the vehicle intercom whether "the farmhouse over there is 1.8km or 2km..." so I would join in with my unwanted opinion!
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I do get what your saying about needing to be able to do it the old way...We were on the range one day, watching some tankies blatting away at targets at unkown ranges...They were in Challenger 1s and their firecontrol system made mice meat of the static targets...However when their lazer range finders were disabled with masking tape by the DS and they had to go back to "steam gunnery" it was a different matter and they did no better than us..

Regards,

Peter
 
G

Guest

Guest
Re: Fieldcraft ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pete E</div><div class="ubbcode-body">Lindy,However when their lazer range finders were disabled with masking tape by the DS and they had to go back to "steam gunnery" it was a different matter and they did no better than us</div></div>

An that is the crux of this thread, shit breaks but mission completion is the task at hand. If one can't read/range the target within his error range, do we just give up an go home, no we just get closer.

Those that have been back slapped by Murphy, always prepare for his entrance, no matter the task.