Efficiency, powder choice, and OAL

[Shrinkmd]

I was at the range and finally fired off my 223 Rem reloads, as well as some Prvi M193 to compare. I was using Wolf 223REM primers, and AA2230, and once fired WCC04 cases. I made up some starting loads at 22.5 gr, and also some more at 0.5 gr intervals up to 24.0 gr. 20" barrel on these numbers.

Funny thing is, my 24.0 gr load had a lower ES and SD than the Prvi factory (although it averaged 2878, whereas the M193 zipped out at 3110) My best SD was 20, and the factory was 29.1 Interestingly, my lower loads had much higher spreads and SD, around 38.

I am assuming that as the powder fills up the case more, you get the more efficient load. But if you go too hot, it causes other problems and reduces accuracy? I don't have good group sizes for these, I really, really need a better rifle rest.

On a related note, do people think you would get more accuracy with a fast powder like Bullseye by seating deeper to get more efficiency (still way above minimum OAL) or trying to seat as close to the lands as possible, for decreased bullet jump?

 

[7.62 Nato]

What weight bullets? I've gotten good results from 24.5gr. of TAC under a 55gr. FMJ. I plan on doing some heavier bullets for my Bushy (1/9) and some lighter, faster loads for my Rem. 700 (1/12).

 

[Shrinkmd]

Oops, forgot those details. The bullets are Hornady bulk 55gr FMJBT and it is out of a 20" 1:9 Bushmaster.

 

[dcl]

My AR loves the AA2230+ hornady 55 gr. fmj combo. Im using Lake City brass with CCI primers. As you stated very low SD. I am running just under max loads and getting better accuracy than at the lower end of the powder scale. But as always use caution. This load has become my go-to load. dcl

 

[243winxb]

Bullseye in a 223, are you crazy, see a shrink. lol. Use a match grade bullet for better accuracy.

 

[Walkalong]

Those 55 gr bullets are not intended to be target bullets, just cheap blasting plinking bullets. The Hornady 55's do seem to be a bit better than many of the bulk 55's though. A change to a quality bullet will shrink groups faster than anything else right now.

And scratch the Bullseye idea.

 

[243winxb]

A must read for 223/5.56 handloaders> http://www.6mmbr.com/223Rem.html You will find Sierra Reloading Data if you click the Icons.

 

[rcmodel]

A change to a quality bullet will shrink groups faster than anything else right now.

+1
Forget all the dinking with powders & charges until you get some accurate bullets.

FMJ are at the bottom of the food chain accuracy wise.

I can guarentee you will cut your group size at least in half or more by switching to V-Max, Ballistic Tip, HP Match, or about any other bullet with the jacket hole in front.

Here are groups from my Colt carbine shooting the same exact load with 55 grain Winchester FMJ-BT and 55 grain V-Max.
Guess which one is which!



rc

 

[Kernel]

I am assuming that as the powder fills up the case more, you get the more efficient load.

I don’t believe that assumption is true as a Rule. Sometimes it holds. Often times it will not. Ideal Load Density will vary from powder to powder, cartridge to cartridge, and bullet to bullet. Perhaps it’s true in this case, with your combination of variables, but you have more work to do to prove the point.

Load Density is the handloading term defined as the ratio of the space occupied by powder vs. the empty space under the bullet. In general, handloaders will have best results when the LD is between 85% to 105%. With a LD over 100% being a compressed load.

In general be careful using the term “efficiency”. It’s a relative term that can be defined a thousand different ways. In the context of your original post, how do you define it?

 

[Shrinkmd]

Oops

I was going to write more in the post about some 9mm loads I was also working up. No Bullseye in 223Rem for me!

 

[mongoose33]

RC, what is it specifically that makes FMJBT less accurate than the other bullets you mentioned? Is it that the center of mass is further back w/ the hollow points? What?

I was out last weekend for the first time trying to evaluate my M4 at 100 yards. Scoped, on a rest.

I did fairly well with 748 at 26.5gr, produced a couple of pretty good groups, I thought, both like this:

But I also got some with the 748 that looked more like the below:



H322 at 24.0gr:

With the groups w/ 748 that weren't as good, I wasn't sure if it was me, or the fact that the barrel was hot (cooler produced better). Or something else.

I'm beginning the quest to see what works and what doesn't, not that I'll do any competition, just to see what I can do.

So I'm guessing I should stop w/ the FMJBT and buy something better for load development. Any particular recommendations of something that's close to the FMJBT where working up the loads will be easier (closer) to what I'm already shooting? It looks from your pic of the target you're using...26.3gr of W748? Can't tell for sure--they're the same load?

 

[Walkalong]

The base is the biggest reason. Check them out. Very inconsistent, and even if they were more consistent, they can't beat a nice flat uniform base of a HP or SP etc., where the opening of the jacket is on the front end.

 

[Kernel]

what specifically that makes FMJBT less accurate

I think a lot of it is just QC from the manufacturer - variations in jacket thickness, tiny shifts in center of gravity, small imperfections. They know it's basically a throw away bullet, so they don't put as much effort in to it. That's one reason why they're so much cheaper, easier to make and fewer rejects.