Primer differences?

[mbreitba]

I've just recently started loading my own for my .223 (thanks all for the suggestions in my previous thread.

I've found a lot of different loads with different primers - do they make that much of a difference, and what is the perceptible difference?

I've found several loads that use a CCI SRM primer, but with the lightened trigger/hammer srping that I have in my AR-15, I had 2 FTF's out of 50 loaded rounds. I've had no FTF's with winchester primers, or federal 205M's.

After waiting the obvious 2-3 minutes after the FTF, I pulled the rounds and saved them for later inspection. After pulling the bullets, I found that both had full powder charges, and the primers simply failed to ignite. I'm guessing that the use of magnum primers and a lighter hammer spring were the cause of the FTF's.

My biggest question though is this - what effects will I see by switching to a 205M or a Winchester SR primer in a load (that being the only change) The round in question is running 25gr of H335 with a 55Gr FMJBT bullet.

[Creeper]

The quality and consistency of primers can effect the accuracy of your hand-loads... but really only if you're building match quality ammunition.

I shoot a 6PPC in LV & HV class benchrest, so I think I have a bit of qualification regarding the quality and functionality of small primers.

If you're not cutting primer pockets, matching case weights, turning necks, hand seating primers, trimming neck lengths and accurately controlling neck tension to the .0005" place... in other words building match grade hand-loads, then using reliable primers are more an issue for you than using match quality primers.

Saying all that... Federal 205M primers are benchrest quality, and I've never had a primer related FTF in well over 100,000 match rounds, so if you can obtain them easily and for a reasonable price, those would be the ones to stock up on.

All IMO of course,
C

[mbreitba]

Match quality - not yet. I like shooting my AR, and we have a HUGE coyote problem here in central Iowa. I can find pretty much all of the coyote hunting ground that I want just by driving down gravel roads.

That being said - yes, reliability is my main concern, especially with a slightly lighter hammer/trigger spring combo (currently about 4 pounds). From what I can tell, the magnum primers are the "heavy duty" primers, which include a bigger charge, and thicker walls, correct?

Basically though, anything that fires in my gun will be pretty much the same when I hit the range? I'm not looking for perfection, but staying under 1 MOA is definately something that I want to do.

[Creeper]

There's no reason to use magnum primers in a .223 semi-auto rifle. Stick with Federal, Winchester or CCI standard small rifle primers and you'll be fine.

There are a lot of aspects to getting a consistent 1 MOA from a rifle/ammo/optic/shooter... best of luck finding the combination, which is half the fun of it.

C

[Sevens]

Just a quick note-- obvious to many, but might help if you aren't aware.

When you see listed data, they always list the primer type but that's only because they always list most everything. They tell you the bullet weight, style and who made it. They often tell you the length of the barrel it was fired in, and they always tell you the primer they used.

That doesn't mean you must use exactly the same bullet, you don't have to have the same length barrel and you aren't forced to use the same primer.

They give that information because it's relevant, not because it's required. The data you are looking at is a guideline, a set of parameters to work with. You start lower and work toward it, double and triple checking that data with other published sources.

You can use any brand of primer you wish. Some powders (and the data you find for them) will state the use of a magnum primer and it's a good idea to use them, and it's not a good idea to use a magnum primer with data that doesn't call for it without reducing the load significantly.

What you should do is find a good deal on small rifle primers, then buy 2000 or 3000 of them and work your loads up with those primers.

[crowbeaner]

When loading the 222 and 223, I use RP 7 1/2 primers unless the loads are to be fired in a semiauto. Then I switch to CCIs to be sure that the primer goes pop when the firing pin hits. Uniforming the primer pockets and flash holes are the 2 most simple steps to benchrest accuracy and they both only have to be done once in the life of your cases. A good powder measure is your most important piece of equipment next to an accurate scale.

[REMINGTON DUDE]

I Have Heard Some Handloaders Say That Cci Primers Are Deffintly Harder, Sometimes Too Hard, You Could Try Another Brand And See If It Takes Care Of The Problem

[Unclenick]

In Handloader #248 (Aug-Sept 2007), Charles Petty did an experiment with several brands of primers, using them to light the same weighed charges of 24 grains of Reloader 10X in new Winchester cases under the 52 grain Hornady A-max bullet seated to kiss the rifling of his Cooper Phoenix in .223. The muzzle velocity (MV) variation and extreme spread was measured for 5 groups of 5 (25 shots), and the averages varied from about 3146 fps (Federal 205) to 3330 fps (Remington 6 1/2). Roughly speaking, the primer difference amounted to what you would see with a 6.5% change in the RL 10X powder charge, and his peak pressure varied about 11% by QuickLOAD calculation.

Petty's smallest groups came from Remington 7 1/2 primers (small rifle benchrest), which averaged 3305 fps MV with an average extreme spread of 50 fps. His most consistent MV load used Federal 205M primers, with 3187 fps average MV and 16 fps extreme spread. That the Federal was less accurate was likely a function of his barrel time being longer with the lower pressure produced, which moved Petty off a sweet spot. He would have needed a grain more RL10X with the 205M to bring the barrel time down to match that of the 7 1/2 primed load. This does seem to illustrate, though, why benchrest shooters tend to prefer milder primers; they let the precision of the powder charge govern the velocity variation more than the primer does.

The bottom line is, changing primer brands is enough to matter. Note that small rifle primers are not normally made in a magnum priming mix, but CCI #41 is likely pretty close in order to meet military low temperature ignition requirements. So velocity and pressure might well have gone still higher with those. The old rule to knock your loads down 10% and work them back up whenever you change a component applies. I would add that it is best to change only one component at a time to see its effect.

Nick

[ratdog]

Sorry to bring up an old thread but....


Crow...What are your issues with RP 7.5 primers? Just wondering as I just got a bunch for use in a semi auto.

[Unclenick]

The CCI's he's referring to are the #41 military hardness primers which are considered a little safer from slam fires in guns like the AR that have floating firing pins. Personally, I've fired lots and lots of Federal 205m's in my AR with no problem, and they are considered among the most sensitive. Just be sure your gun's bolt components are all within spec and that your cases are fully resized and that your primers seat slightly below flush with the casehead (0.004" is nominal). Uniform the depth of the pockets with the appropriate tool if necessary to achieve that and you will likely be fine. Never chamber a round unless the range is hot and the gun is pointing safely downrange toward the backstop.

[swmike]

The #41 primers are the "harder" primers designed to prevent slamfires in the ar as Unklenick stated. Some loaders use the Small Rifle Magnum primers as they too are a little harder in order to stand up to the extra "poof". I am using the Wolf .223 Small Rifle Primers which are purported to be a magnum primer. The cup is supposed to be a little over .6mm in thickness.

May not be good for a lightened hammer spring but with a stock AR spring it is just fine.

[ratdog]

Good advice Unclenick...

So I take it that Remington 7.5 primers are good to go

[amamnn]

In an AR or any gas gun, you want to be sure that you are seating the primer at least .003" below flush. It is also critical in any match load to ensure all primers are seated in uniformed pockets at the same "crush" - many if not most match shooters feel that primers are seated correctly when and if .001" of extra depth is "crushed" after the primer hits bottom.

I read the article Nick mentions in Handloader and frankly cannot remember whether the author had the equipment and expertise to do that.

I've seen other tests of primers in Precision Shooting and other places that had different results. Some of the authors did have the proper tools to ensure all primers were seated uniformly.

As far as I know, there is only one tool that shows you exactly where you have seated a primer. Doing it by "feel" has been dramatically proven to me not to work. Using a primer pocket uniformer does not always mean you have made all pockets uniform. It only means you've cut brass out of the ones that were shallow. I bought the K&M primer seater and found out how far off I (and much to their chagrin a few other shooters) was with all this.

You can also check your primers depth below flush with the rear end of any good quality caliper. This does not show you how close to the bottom your primer is, not the crush, if any, nor whether all pockets are uniform.

A useful and interesting feature in Precision Shooting is the match result section at the end of the magazine. Mainly, these are BR results but not 100% and are still highly informative. Many of the folks shooting report their actions, barrel, powder, stock, bullet and primer choices to the PS stringers for publication. This issue, as I usually see in every issue the primers used by competitors were mainly Federals; something like 98% as compared to any other brand.


Sierra has some interesting things to say about primers and related issues as concerns loading for gas guns:
http://www.exteriorballistics.com/re...sgunreload.cfm

[Unclenick]

I don't recall whether Petty mentioned his priming gear or not? He has a technical background, so he may have done OK? I felt the telling thing was the extreme spreads he got were so much lower with the Federal 205M's. That suggests he had fair consistency in seating primers. On the other hand, he didn't seem to know to tune the loads to best accuracy for the primer he was using instead of using the same charge in them all. It wound up giving at least an indication of their relative strength by averaging the resulting MV differences.

RWS primers also find favor with some benchrest shooters.