5.56 load data with Barnes 55 gr JHP-FB

[snolden]

I am in the process of working up some loads with these bullets for my AR.
Powder: TAC
Primer: CCI SR
Case: WCC 14 and R-P .223
Bullet: Barnes 55gr JHP-FB (cup-n-core style)
Rifle: 5.56 S&W M&P 15 with 16" military contour barrel

I have looked everywhere for good data on the Barnes 55 gr JHP-FB bullets I bought from Midway. Barnes book, emailed them (waiting on response), Ramshot load data etc.

So, here are a couple things I ran into.
At 25.6 gr of TAC I started seeing raised primers with minimal brass stretching. Velocity was 2945 or so (I only shot two rounds). THIS ONLY HAPPENED IN THE R-P BRASS.

The NATO brass by Winchester (WCC14) had no problems and at 25.6 grains of TAC I shot .9" groups(2) at 3010 fps. I don't know why the difference in velocity other than the small sample size (2) for the R-P brass load.

I have found some similar data that shows as high as 27.4 grains for flat based cup & core bullets. So I was surprised to see the raised primers. One was flush, one was slightly above the rim.

My COL is 2.230 with this load. I put on just enough crimp so I can drop them several times without the length changing. I drop them ~2' onto my wooden bench to check. The bullet size consistency is good but not great. COAL varies by +.004/-0.000 through the 50 I have loaded so far

Those groups were with an Eotech so the bullets are VERY promising. I have had zero luck with this rifle and 55gr bullets until now.

Extraction is amazingly consistent and all brass lands within about 18" so far.

Sean

 

[Panfisher]

From what I could see on the Ramshot data site, looks like you might be on the upper end for load data but certainly not into dangerous territory by any means. I bought a box of the Barnes 55 gr. FBHP's from Midway for plinking bullets but am planning on loading them either with BLC-2 or IMR 4895, haven't tested either load yet though.

 

[steve4102]

You are almost two(2) full grains below Max according to Ramshot.

At 25.6 gr of TAC I started seeing raised primers with minimal brass stretching.

What is a Raised primer?

What is Brass stretching and how did you measure this "Stretch?

 

[somerled]

The velocity will be different between the load using the R-P .223 brass and the identical load in the Winchester 5.56 NATO brass because of the different case capacities. 5.56 NATO brass is thicker than .223 commercial brass.

 

[snolden]

Yeah I know these things. Brass stretching is the case elongated more than normal measured with calipers. A raised primer is one that is backing out of the primer pocket due to either a stretched pocket or over pressure.

I know I am below max, I didn't know it was two full grains for this bullet. That is why I am trying to get word out so you guys watch out for this early on like I did.

I didn't expect to see press signs this low either.

.223 and 5.56 brass are MUCH closer capacity than you think. Usually the samein my measurements. I don't buy the much thicker argument.

 

[steve4102]

Yeah I know these things. Brass stretching is the case elongated more than normal measured with calipers. A raised primer is one that is backing out of the primer pocket due to either a stretched pocket or over pressure.

I know I am below max, I didn't know it was two full grains for this bullet. That is why I am trying to get word out so you guys watch out for this early on like I did.

I didn't expect to see press signs this low either.

.223 and 5.56 brass are MUCH closer capacity than you think. Usually the samein my measurements. I don't buy the much thicker argument.

A "Backed Out" primer is usually caused by a load that is way UNDER pressure, not over pressure.

Where are you measuring this "Stretching" from? Case head to datum, case head to case mouth? What part of your cases become "elongated" after firing.

 

[snolden]

Okay, thanks. For whatever reason, that load has issues that I am not comfortable with. I am not going to proceed.

Yes, brass stretching in a semi auto is a bit hard to read. I don't measure anything following firing. I go by how much force is required to resize it and if it is exceptionally long/short prior to trimming. None of the test rounds require abnormal force or trimming compared to other .223 factory loads I have run through this rifle.

I only have about 10 years and 6 calibers experience in reloading (albeit 10,000+/- rounds) so I don't push too hard. If I see something that isn't normal, I just stop.