Could anyone help me with the Ballistic Coefficient  and bullet speed for Barnes 5.56x45 69gr OTM BT? I am trying to punch the data is my iStrelok app.

Also for the IMI Razorcore 77gr?

For 77gr Razor Core, I've been using ballpark of 2800 FPS to start with in an 18". Another Texas Mk12 guy chrono'd his at 2844 Avg with temp in the 70s. Start there and tweak the MV in the app based on how you see it work at 200, 300, etc.

For BC I use .362 based off the Sierra page for the 77gr SMK.


In my 16" I used 2750 and started adjusting from there.

Im not sure what bullet for the barnes you are talking about and we would need your barrel information for 'bullet speed' which would be the velocity.  

For the IMI razor core 77 grain I believe most people use the standard 77 SMK value of .362.  as far as the velocity if you are using a 16 inch barrel you can plug 2620.  Be sure to have a wylde or 5.56 chamber as it is 5.56 and is pretty hot.  If you have a different barrel length you can pretty easily look around and find someone with that length and in the same region as you that can share velocity data.  So what barnes round are you referring to?

16" Noveske SS barrel
Not sure on the Barnes. The OTM BT was straight off the box. It appears to be a  hollow tip and has me a little
Concerned due to some tarnish or spots on the copper jacket of the bullet. Never used it before , I just ordered it from Natchez in attempt to find something this rifle likes.


Thank y'all for the help!

No problem man.

I had one of the Noveske SS 16 inch recon barrels and it really liked the light loads.  All barrels are different but I shot the moa challenge using 52 grain rounds using irons for just a hair over 1 moa.  I don't load them for the shorter guns but have been working up a load for my 24 inch telephone pole gun.  

Looks like your BC should plug in at either .224 or .225 out of your barrel I would guess they are traveling in the mid 2900 FPS range.  I haven't shot the specific load you are talking about but the name would imply that it is an open tip match (the hollow point you referenced) that is boat tailed.  Most of the 52s that I shoot and load are the flat base versions.  I included a picture of the 77 smk and 52 fb just because I could and figured some one might like to see the difference.  For close in shooting on paper in that precision 100-200 yard range 52s are great.  The 77s can fight wind and hang in there over longer ranges and can make repeatable hits out to 900-1000 yards if you have large enough steel and can play the wind.  I have enjoyed playing with 69 grain bullets lately and across the mid band of 200-600 yards it has been very enjoyable to shoot.  Any of the bullets can reach out and try to do the job of the others and if you are entering them into a calc I would assume you are going out further.  If that is the case the 52 probably isn't gonna be a winner for you.  Im also not assuming you don't know this stuff I am just writing it out so that other people who look at it might get a full picture.

Awesome! Thank you. I am new to this, I have always just shot mil-spec ammo (62gr & 77gr) & some match 223 (75 &77gr) and then the bug hit me. I want tighter groups out of my ar15 platform, local range goes to 300yrds. But I am planning on going to another range that has 1000yrd capability,  or that I would go that far. I am open to all and any suggestions, I am looking into reloading in the very near future. Just wanted to find something that shot well (factory) to give me a starting point. I am open to all suggestions. I was under the impression that heavier grain bullets where the way to go for tighter groups and/at longer distance, but if I am thinking wrong please tell me!

If the end goal is to shoot out at 1000 it makes sense just to get the rounds that will work for you.  You have started out with the IMI which is a good load with a lower cost.  Another option is CBC/MAGTECH 77.  Both have good velocities with decent standard deviations while staying relatively cheap.  

There is a stalemate between quantity and quality here.  To get to know a rifle you really need to shoot a bunch of rounds.  Texas is great because you have ranges that you can easily see the impact.  Up here in the north when I go out shooting it is almost always grass land and anything not on steel that a spotter didn't see trace on is just lost data.  If I were you I would grab up a bunch of which ever round initially looks pretty decent and shoot the piss out of the round.  Reloading and tinkering is a hobby for me.  If I want to just grab a gun and go out and ping steel at 700 yards I just grab a couple boxes of CBC and get to it.  The difference between 1.2 moa and .6 moa might cost you hours of work and up to a dollar more per round to fire but a 1.2 moa bullet with a good shooter who knows how to work the wind can ping 10 inch steel at 700 yards where as the best bullet you can buy with a bad wind call will almost always miss.  Get a decent quality with a larger quantity and get your data ironed out.  

Its a lot of fun and can be really frustrating.

Thanks again. I have been kicking idea of rebarreling this rifle to a 18 or 20".  But I figured I would see what it can do first. What is considered the cat's meow on barrels these days? LaRue, LW, Noveske, Rainer? I also realize that my choice in optics (1-6 Razor) is also a limiting factor for me.

OK. Could someone offer some advice to improve my groups? Or am I expecting too much? Is this on par?

Setup:
16"Noveske SS barrel with Saker762 on a Mega upper/lower
          Rifle was in a lead sled with no weight & I had to readjust after every shot
          Scope is Vortex 6x, so that is a limiting factor for me.


Environment:
100yards
52 degrees
97 % humidity
5-7 cross wind at times, but the range is pretty perfected from wind(old Quarry)

Ammo used:
-IMI 77gr 556
-Barnes 69gr OTM 556
-Federal 77gr Sierra Match King 223
-Hornaday 75gr Match 223

What trigger are you using? When shooting for smallest possible groups I do prefer a bit more magnification. With the IMI I think you're pretty close to what it's capable of. Also try to go with more than a 3 shot group; at least 5, preferably 10 to get a better picture of the loads' capability.

Giessle SSA
Will do at least 5 shot group next time.
Yea. At 6 power doesn't really cut it for me. I need a little more magnification.What should I look into next? I currently have Vortex Razor 1-6


How long should I wait for the barrel to cool in-between groups?