M14 Forum

SAPPNASTY

Although not my first reloads, today was the first opportunity I had to run a few through the Chrony. Here is what I loaded and here were my results.

Load info:

Powder: IMR 4895
Powder Weight: 22.7 grains
Primers: CCI No. 400 Small Rifle (seated just below flush)
Brass: Lake City 07 with NATO stamp (once fired before this)
Bullet: 55 grain Hornady V-Max w/ Cannelure
Trimed to Length: 1.750"
Overall length: 2.184"

Chrony Info:

I fired a total of 10 shots (running out of daylight) and this was the results.

Shot 1.) 2,411 fps
Shot 2.) 2,428 fps
Shot 3.) 2,408 fps
Shot 4.) 2,402 fps
Shot 5.) 2,390 fps
Shot 6.) 2,416 fps
Shot 7.) 2,416 fps
Shot 8.) 2,413 fps
Shot 9.) 2,428 fps
Shot 10.) 2, 380 fps

All ten shots averaged at 2,409 fps. I have a few questions now that you have the data. First question, since I have never Chrony'd anything, are my variations in FPS normal, or do my hand loads need improvement? For the most part they were all within 50 fps of each other. Second question is, according to Hornady's 8th edition reloading book, this load should be traveling 2,800 FPS??? What did I do wrong to be so far below what the load data states? Third question is, the load data book said it was fired from a 26" 1:12 twist Remington 700 barrel. Would the fact that my barrel on my AR-15 is only 16" change the FPS that much? That is all for now, I will have a ton more data when I finally get a full day at the range. I'm hoping RAMMAC will chime in on this one...help anyone?

-Sapp

m14nm

I'm no expert but they look pretty good, a little slow, maybe. I think somewhere around 30ft. per second, per inch, is what you can expect to loose.

Just my opinion.

SAPPNASTY

This was the first time I reloaded for this particular AR-15, so I started at the lower end of the spectrum and figured I would work my way up.

Bamban

Extreme spread is about normal. Excellent start, as noted a little slow. Some of the guys in my club load 69 SMKs with 24 grains of I4895.

Here is a compiled list of known AR match loads for your reference. http://njhighpower.com/

SAPPNASTY

Thank you Bamban, Even though I have been loading rounds for nearly 2 years, I still feel that I am a rookie and need all the help I can get!

stickboy

I load for my 16" AR, and your spread looks normal to me.

Hey you did not shoot the chrony, so your off to a good start!

My plinking load for my 1-9 twist 16" barrel is 25 gr of AA2230 in military brass of mixed manufacturer. CCI#41 primer. I average about 2900 fps.

Just work your way up slowly and watch for pressure signs. Good move on being cautious. And yes, there can big a big difference between load data book velocity and your real velocity. Just use common sense, and like I said watch for the warning signs of too much.

RAMMAC

Average velocity is 2409
Standard Deviation is about 15
And the extreme spread is 48

Most people agree that a standard deviation of 25 or less means that you are doing a good job keeping your loads consistent. I usually get somewhere between 10 and 15 for a standard deviation, my really picky loads will get just under 10.

The barrel length difference will drop the velocity quite a bit. QuickLOAD came up with a number that was pretty close to the 2800 fps mark when I used a 26" barrel. I actually got 2820 fps but I would expect there to be small differences since I can't duplicate the actual bullet length (the bullet, not the entire cartridge) and case volume that Hornady had during testing.

When I changed the barrel to 16" the predicted velocity dropped to 2462 fps, 358 fps less or 35.8 fps per inch. But that was using an overall length of 2.250" which is what Hornady listed in their reloading manual. You stated that you used an overall length of 2.184" and when I reduce the COAL to match that, the velocity goes up to 2496 fps. Don't expect that 35.8 fps per inch value to hold true across any variety of barrels, bullet weights, or calibers, I've read that all those factors will change how much the bullet's speed will varies in relation to barrel length.

Then there is one more factor that could have dropped the velocity, the air temperature. the calculations so far were based on a powder temperature of 70 degrees F. If we drop the temp to 40 degrees, then the velocity drops to 2437 fps. IMR powders vary quite a bit with temperature and in this case you could estimate that the velocity will drop about 2 fps per degree.

SAPPNASTY

RAMMAC,

I was hoping that you would see my post as I always value your reloading information. The temperature was a nice 79 degrees today while at the range. The only reason I made the overall length 2.184" is because the bullet had a cannelure and that was where the bullet sat where the case next touched the middle of the cannelure (I did not crimp). It seemed a little to far in to me, but it shot great. I was not so much concerned with accuracy today as I was on the fps averages. That really says it all and I am very maticulous when reloading. I try to make sure everything is perfect and started off with some very good habits suggested by other members, including yourself. Not to sound like a dumbass, but what in the hell is standard deviation? Seems that 15 is good, so that is a big relief! Thanks again for the info. I would like to kick them up a notch, so what do you think a good all around load up would be using all of the same components using the same rifle? I have no Chrony'd any of my M1A or Garand ammo yet....and I am even more careful with that. Hopefully they shoot just as good.

-Sapp

RAMMAC

Basically standard deviation is just a measure of how much the velocities vary around the average. The lower numbers mean that there isn't much variance in the velocities.

I'm don't own an AR and I don't load for them so I'd trust Bamban and Stickboy's numbers. QuickLOAD predicts that the max would probably be around 27gr of IMR 4895 in regards to pressure but for accuracy my guess is that Bamban's recommendation of about 24 or so grains would give you pretty good groups. I'll bet that if you play with loads from 24 to 25 grains you'll find that secret spot.

valken

I don't reload for 5.56 but I am a bit confused. I crony some ss109 out of my 16 inchers and was running around 2900 fps with 62 grains ss109. Why is his 55 grains so low?

RAMMAC

The powder charge and type is completely different than your cartridges. If he increases the powder charge weight, using the IMR 4895 powder, to around 26 grains he would get the same kind of speed you are getting. By the way, the M855 (SS 109) uses about 26.1gr of WC 844 powder according to published specs.

valken

So he just running low fps?

RAMMAC

Yup, he wanted to start low and work his way up, which is the safe way to develop any load. Never trust that other people's loads will work safely in your weapon.

Al Mack

It's good to start low with the ar's. Reason being they now have three chambers the 556, 223 and the wilder I think it's called. It is supposed to be able to shoot 223 and 556 safely. 26.5 to 27.5 of 4895 should safe and accurate.

SAPPNASTY

Next time I will jump to 24 grains and see how it shoots and what my averages are. I would rather start low and work up them blowing my face off with and unsafe load. I think that I am going to take everyone's advice and play between 24 and 25 grains. I haven't experimented with and heavier or lighter loads yet, but wanted to ask which bullet weight would work best with my Daniel Defense 1:7 twist 16" barrel? 55 grains seem to shoot okat but I bet a heavier bullet shoots better. Just gotta buy some different ones and try em out I guess.