M14 and 168 gr TAP at 1000 yards

[Dark Horse]

The question of whether or not the 168 gr AMAX will remain stable at 1000 yards seems to come up often so I thought I would share a day at the range at that distance. JBM has been perfect so far with this round up to 600 yards. Said I should have needed 11.1 mils to get to 1000. Only had 10.7 left in the scope so had to dial down 10.1 and held at the first mil hash mark. Still came up low, so I ended up with 11.9 total once zeroed. Don't quite understand where the extra .8 mils came from but the round in question had no problem getting there.

Conditions:
71 Degrees
55% Humidity
29.88 Hg
281 ft Elevation

Rifle Specs:
LRB M25 Receiver
22" Krieger Heavy Barrel
LAW 483 stock
Schmidt&Bender 3-12x50 P4f
MV average 2700 fps

Last 5 shot group of the day

 

[daxromana]

Re: M14 and 168 gr TAP at 1000 yards

Glad to know this. I want to shoot my M1A at 1000 this summer and it did not seem to like the 175SMK. I was going to play with the Berger 155.5, buti would be happy with that group. Good enough to clean it.

 

[Dark Horse]

Re: M14 and 168 gr TAP at 1000 yards

Can any of the ballistic experts elaborate on why I needed .8 mils more than JBM was calling for? As I stated, it has been dead on right up to 600 yards using a G7 bc of .230 for the 168 gr. AMAX.

 

[kmussack]

Re: M14 and 168 gr TAP at 1000 yards

Have you calibrated the elevation adjustment of your scope?

 

[Dark Horse]

Re: M14 and 168 gr TAP at 1000 yards

If it's right on with JBM up to 600 yards and always returns to zero, wouldn't that mean it was calibrated?

 

[vereceleritas]

Re: M14 and 168 gr TAP at 1000 yards

Well I'm definitely no expert so take this for what its worth. Could it be that the A-maxes are going subsonic before they reach 1000yds? That would change their BC mid-flight, right? Don't know if your ballistic software takes that into account.

 

[bricktop]

Re: M14 and 168 gr TAP at 1000 yards

Is your velocity measured or estimated? I think 2700 is on the hot side for a 168 gr bullet out of the M14 22" barrel. One of my hotter 168 gr loads runs at 2680 fps, where FGMM168 runs at around 2620 avg. If you bump it down to 2650 or so, then the 11.8 mils starts to look mo' betta, while it only changes ~0.2 mils at 600 yards. Is your sight height correct as well?

 

[Grump]

Re: M14 and 168 gr TAP at 1000 yards

That \/ \/ \/

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bricktop</div><div class="ubbcode-body">Is your velocity measured or estimated? I think 2700 is on the hot side for a 168 gr bullet out of the M14 22" barrel. One of my hotter 168 gr loads runs at 2680 fps, where FGMM168 runs at around 2620 avg. If you bump it down to 2650 or so, then the 11.8 mils starts to look mo' betta, while it only changes ~0.2 mils at 600 yards. Is your sight height correct as well? </div></div>

Beyond 600, humidity and a true measure of barometric pressure can start having an effect. But the starting point is always an accurate velocity reading. I've had the same ammo differ by 30 fps average, at the same temperature and shooting spot, just on different days. Atmospherics and altitude sure aren't going to affect my velocity at 8 feet midpoint from the muzzle, you know!

I'm not sure that a 2700 fps load with a 168 could really stay in spec with a 22-inch barrel. That, or a slower powder could be pushing port pressure above 14,500 CUP/16,500 Peizo. That would not be long-term smart.

 

[Dark Horse]

Re: M14 and 168 gr TAP at 1000 yards

I just went through some notes and checked the chrono numbers with my CED Millenium and it averaged 2675 for 15 shots. That was collected on a 70 degree day. Sight height is 2.1".

I have spoken to several sources such as Hornady, Springfield, and Ted Brown who built the rifle and all have stated that the 168 gr Hornady TAP is safe for the M14. Can't hurt to run the chrono again and contact Hornady about the powder burn rate.

The grouping was great all morning so I would think that the velocity remained somewhat consistent from shot to shot or it would've had more of an effect on the vertical at that range.

 

[seabass25]

Re: M14 and 168 gr TAP at 1000 yards

Is that a mcmillian stock? How do you like it?

 

[M21guy]

Re: M14 and 168 gr TAP at 1000 yards

TAP is completely safe for an M1a. I wish they factory loaded their 178gr Amax in it. I'll probably someplace down the road be trying the new superformance ammo line from them. Yes I know, it is a little hot velocity wise, but what the hell. I do run a grooved piston just for the bleed off it provides. We'll see what how it all works out this summer. I just got to find my way to a 1000yard range.

Sweet rifle btw...