reading the primers

T

tiny68

Member
Been a while since I loaded any 223s up and then it was all cookbook straight from the manual. Loading 65 gr Sierra Gamekings into FL sized LC brass with Fed205M primers. Powder is Varget. The Hodgdon website list 24.5 to 26.4 gr with 63 gr SPs. I used this as a basis to build a load latter from 24.5 to 26.6 gr in 0.3 gr steps. Below is a pic of the primers. Bottom row is 25.5 gr of Varget I made up as fowlers. Second and third rows going from left to right are the latters. Identical repeats between second and third row.
Here's the problem. I usually always closely watch the primers for flatness for an indication of reaching a max load as well as bolt stiffness when removing the case. If I look at the bottom row these appear pretty hot to me with significant flattening.

With safety glass on, I went and fired the first latter. No bolt stiffness at all. Primers look bad. Shot these over a chrony and velocities where 200 fps lower that the manual for the 63 gr. I don't know how close the bearing surface match on these bullets. Second latter gave identical results.

So, are these too hot at the top of the latter? Or do some guns/cartridges produce flatter primers than others? I have been shooting a 30BR a lot recently and I generally shoot it wide open and flat primers are the norm.

By the way, loads 5-7 in the latter group less than 1" at 300 yds on both strings. Around 26.0 grs is definitely a sweet spot. And this was done with a Stevens and a $65 new-take barrel I just got. 1:9 twist - 22".

The top row is el cheapo import 55 gr ball I have that I used to sight the scope with. My smaller primer identions on all of those.

What do you think? 26.0 grs ok?

tiny
http://i159.photobucket.com/albums/t151/tiny68_photos/223primers.jpg
 
The key here may be that you full length sized the cases.

If by sizing you make the round a sloppy fit in the chamber, then on firing, the case can be run forward in the chamber by the firing pin before, or as a part of the ignition process. Ignition can back the primer out of the case until it contacts the bolt face, then the case expands back too, which can peen over the primer & give the appearance of excessive pressure.

I would try adjusting your sizing die until the cases fit the chamber with the merest hint of resistance, then back it in a tad so they're a perfect fit with minimum headspace.

However, I checked the Aussie ADI Powder site for AR 2208 (that's Varget to you) & they list 22.5-25 grains for a load with 62s. Hodgdon may be a tad optomistic with their loads in this instance, though your velocity results seem to contradict that. Maybe we're just a tad more conservative over here.

http://www.adi-limited.com/handloaders-guide/rifle.asp

John
 
I have the sizing die set to get me a bump only. I set this on fire-formed brass. Pushing the shoulders back no more than 0.002-0.003". I am seatting the bullets 0.020" from the lands. Plenty of bullet to come in closer, but I don't want to set hard in the lands with a hunting load.

How much do primers vary in "hardness". Are Federals softer than others?

Tiny
 
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Yes, Federals are reputed to be one of the softer cups, which is why some use them in sloppy pockets - they splay out more under seating force, so the story goes.

While I'm the only guy talking to you, it crossed my mind that the cases in the top of the picture might have showed different primer strikes because they were staked in primers, but that's just one of those little thoughts you get when there's nothing better to involve yourself in.

It did surprise me that ADI (the manufacturer) lists a lighter load than the US distributor of their powders. Maybe some .223 user forum like National Match might have more suggestions.

John
 
Primers

Switch primers to another brand as the Fed primers are soft. I know the PPC guys are using them exclusively in competition, but theyare all using bushed firing pins.

I personally and now using Wolf Small Rifle Magnum* primers and getting very good results. They are harder and go not "blank" like Federals under upper pressure loads.

Primers vary from company to company as to the hardness of the primer cups. This is a very good reason to NOT use primers as a pressure indicator.


* Wolf small rifle and small rifle magnum primers are said to have the same priming compound with the magnum primer cups being harder. My experience is that that "regular" Wolf small rifle primers are way too soft. (The ones I have will end up being used as pistol primers.)

George
 
It appears that the primers are not bad and I think Federal looking, however IF you are positioning the primer deep in the pocket (say .004 or so) and have some headspace (short cases) the resultant primer appearence will occur. One cannot tell pressures from primers alone.
Clarence
 
In the latest Speer Handbook, there's a photo of three fired cases. The primers look identical.

One was a load several grains under max, one was a max, and one was a dangerous pressure load.

Point of the editors? You CANNOT use primer appearance as an absolute guide.

Amen.

A better guide would be a bright smear on the base due to extrusion into the extractor recess.
 
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