Another rifle ammo question.....

I need a little research assistance. I'm trying to move away from our current rifle duty round to one of the rounds suggested by Dr. Roberts. We have 1/9 twist AND 1/7 twist barrels, 16" and 11.5", so I'm looking at the Federal 64 grain TRU as a probably replacement. It'll will work in both barrel twists and I've not heard any bad things about it (other than some reports of bullet back-up, which I hear has also been rectified). And the concern of lead build up on the feed ramp during heavy shooting days due to the exposed lead.

We currently use the Hornady 60 grain TAP. I know of antecdotal evidence that suggests this round is not good for LEO work. I've also read here and on TF about ballistic tip ammo not being ideal.

So on to the matter at hand. I know Doc's list of recommended rounds and I believe his work is outstanding. I used his research extensively when justifying a transition away from laminate vests to woven aramids for my PD. So all I really need is research assistance to prove to the "gun's and sandwiches crowd" that the 60 grain TAP isn't ideal. I wish 75 were an option, but with the 1/9's....well you know the deal.

Specifically I'm looking for a link, report or quote about the 12" minimum pentration recommendation. That should be sufficient to supplement what I already have.

However, feel free to throw out anything that you think may help. Doc has done the hard part (making the recommendation). This is one of those situations where I know it to be trusted and true, I just need to work backward a little to solidify the position.

Edited to add: I think it was Dr. Fackler who recommended the 12" minimum, but I can't seem to find it.

------------------------------ METT-T...it dictates.

Original Post
quote:
Originally posted by basko:
I wish 75 were an option, but with the 1/9's....well you know the deal.


Anecdotal at best. I have an RRA barrel (Wilson) with 1:9 twist and chrome lined cut to 14.5". I can keep Mk262 mod 1 just outside an inch at 100 meters and 75gr TAP FPD at about the same. I would suggest you try it before ruling it out.

The weapon is the one I'm holding in my avatar.

Karl

 -------------------------------------

"You should respect his position if for no other reason than he has the power to send loyalists like Chris and JCustis to crush your little rebellion if you get caught seditiously half stepping. " - basicload

Just one of the Shepherd's sheepdogs. Joshua 24:15 Matthew 10:28

I hear that it's hit or miss (pun) with 75 grain in 1/9. Sometimes it works sometimes it doesn't.

I also think the black hills 69 grain SMK looks like it may be a good choice.

any input?

------------------------------ METT-T...it dictates.

quote:
Originally posted by basko:
I hear that it's hit or miss (pun) with 75 grain in 1/9. Sometimes it works sometimes it doesn't.


Yup, that's what I'd heard, also.

quote:
I also think the black hills 69 grain SMK looks like it may be a good choice.

any input?


Interestingly enough, in my barrel, the groups were just about twice the size for this load as with the Mk262. Still, both shot well enough to be considered good tactical loads for my carbine.

Karl

 -------------------------------------

"You should respect his position if for no other reason than he has the power to send loyalists like Chris and JCustis to crush your little rebellion if you get caught seditiously half stepping. " - basicload

Just one of the Shepherd's sheepdogs. Joshua 24:15 Matthew 10:28

My agancy issues to the men in black dye and velcro federal 60gr Bonded Bear Claw. I dont know of any OIS using this round, but it seems to be a logical choice. I dont know of any factory loads, but a buddy of mine killed a deer with my worked-up load using a Sierra 65gr GameKing. He figured about 18" of penetration. Deer took 3 steps.

 Im not "High Speed", Im "Non-Stick"

Adam21,

They are probably using the Federal 62 gr Tactical (LE223T3) that uses the TBBC bonded JSP; there are numerous OIS incidents using this load. It is especially effective against targets behind intermediate barriers and it is also a good choice with shorter 10-12" barrel lengths.

Basko,

Here is some info on the 64 gr TRU: http://www.tacticalforums.com/cgi-bin/tacticalubb/ultim...f=78;t=000323#000001

The 69 gr SMK OTM is not a bad choice, but it may not be the best, especially if you are going to have any shots into vehicles.

The 12" minimum penetration guideline originated with Dr. Fackler at the Letterman Army Institute of Research Wound Ballistic Laboratory in the mid to late 1980's when he recommended a 10-12" minimum. After much discussion, 12" was made the agreed upon standard following the FBI 1987 wound ballistic symposium and again verified to be an effective criteria at the follow-on FBI 1993 symposium. Every analysis since, including the recent JSWB-IPT testing, has confirmed this as a reasonable benchmark.

Please feel free to contact me offline for further info.
quote:
Originally posted by DocGKR:
Adam21,

They are probably using the Federal 62 gr Tactical (LE223T3) that uses the TBBC bonded JSP; there are numerous OIS incidents using this load. It is especially effective against targets behind intermediate barriers and it is also a good choice with shorter 10-12" barrel lengths.

Basko,

Here is some info on the 64 gr TRU: http://www.tacticalforums.com/cgi-bin/tacticalubb/ultim...f=78;t=000323#000001

The 69 gr SMK OTM is not a bad choice, but it may not be the best, especially if you are going to have any shots into vehicles.

The 12" minimum penetration guideline originated with Dr. Fackler at the Letterman Army Institute of Research Wound Ballistic Laboratory in the mid to late 1980's when he recommended a 10-12" minimum. After much discussion, 12" was made the agreed upon standard following the FBI 1987 wound ballistic symposium and again verified to be an effective criteria at the follow-on FBI 1993 symposium. Every analysis since, including the recent JSWB-IPT testing, has confirmed this as a reasonable benchmark.

Please feel free to contact me offline for further info.


We have been using that load for a year or to, and have also noted that it works accurately with no stability issues in a variety of twist rates and lengths, particularly stuff from 11.5" to 20, with rates including 1:7, 1:9 and 1:12. The Federal rep said that they were not suprised because, while the weight of the projectile is 62 grains, the actual length is about the same as a 55-grain ball, and it is the longer length of M855 that requires the faster twist. Regardless of the "why," it stays accurate through all of our systems and exhibits no sign of keyholing at distance, even through some truly ancient full-sized M16s (in fact, it shot the best groups through those during testing).

I have noted that the act of chambering a round does tend to deform the exposed lead on the tip of the round, but not too badly, and we generally discard rounds after being chambered a few times.

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