Primers

[CZ93X62]

What Lamar said--in bold print and italicized.

Rifle--handgun--and shotgun reloading have different rules and the wide variety of venues that all three get used in can call for varying load development and production regimens.

IME shotshell reloading is the least flexible of the three sub-groups. You gotta stick to the hull--powder--wad column--shot weight recipe quite closely or performance suffers (certainly) and safety can be compromised--as Lamar points out. CREATIVITY is NOT a good thing in that discipline.

I haven't done much low-node loading. I can't write intelligently about whether primer swaps make a huge difference. I know that even in non-shortage times my area of the country has mostly CCI and Winchester primers. This has been true since I made my first shotshell along about 19-ought-70. If I want Rem #6-1/2s, that has meant a 470 miles drive to the Big Reno Gun Show and a stop at Miwall's booth. The only readily available Federals are SP (#100) and LRM (#215)--and those are iffy. With the serial droughts.......I am very glad that I am well-stocked primer-wise. Availability looms large, IOW.

If low-node = 'Sub-sonic', then I have done a bit of that in 30-06 and 9.3 x 62. WLR were used in the loads because it's what I have most of.

 

[RBHarter]

Shot shell loads are not a facet of reloading, it's a different stone in the ring although with things such as the 12 ga FH exercise the lines can blurr a little.

Mag primers in 45 Colts with H110 are essential, 357 well not so much , but it was a full case with nil air space so there's that . Otherwise standard or and sm do what I need throughout.

Rifles big cases with tip up from 25-06' through 45-70 haven't shown me enough thus far at the levels I've worked LRP LPP to worry much over .

The one place that I did have a primer make a big difference was from WLP to CCI in a x39 it closed full pie plate at 50 yd to 3×5 at 100 .

With a 35kpsi loads after 5-6 firings I had to take them up to 9mm and back down to .316 for a false shoulder and form them back out . The chamber was just God awful sloppy . They didn't shorten with the WLP and I now know that they will slam fire in an SKS . I suppose the brass could have been too soft but after a dozen cycles and being up to 9mm and down to .316 twice w/o annealing and 10 short sizings one would think they'd be plenty hard . I don't know if it was the heavy bolt or the firing pin but it made cases short enough to miss the extractor for unloading an unfired round .

 

[popper]

Per L. Gibson article:

I then used the same fire formed case with live primers. In as little as two firings there was a measurable decrease in headspace. After five live primers the fired primer was noticeably backed out after firing.

It is a confusing statement. Let's resolve what he tried to say.
Bottle neck rimless case with say 10 thou. H.S. FP hits primer, (assumed seated completely), primer goes bang. PSI in primer 'cylinder' goes up and primer moves out far enough to force case forward to shoulder 'stop'. Question #1 - is the primer force enough to bang the case into the chamber? Case moving more than 10 thou? Note: AR10 bolt slamming on a 308W case does NOT increase HS.
Then powder ignites, pushing case head BACK against bolt. So case STRETCHES. Primer pushed back into pocket.
Question #2 - (remember, psi x area is force) so small primer cylinder/psi is enough to set the shoulder back but larger cylinder/higher psi isn't enough to stretch case back to original length?
another note - the rifle chamber shoulder is NOT the same as the datum shoulder in a HS gauge. Larry used fireformed cases but what is used to measure HS?
IMHO, from physics point of view - nope, lite load with constricted PP hole cannot cause shoulder setback. We do know that a second FP hit on an improperly seated primer with cause a bang. And I know it takes a lot of force to seat primer fully in some PPs.
Just my 2 cents.

 

[Jeff H]

...lite load with constricted PP hole cannot cause shoulder setback....

Maybe, maybe not, but I did basically what Larry did and noted an increase in primer protrusion over multiple firings of FF/neck-sized cases. I did not use empty FF cases, rather I used one of the really light loads mentioned before. Leaving the case wide open at the mouth, and with nothing inside to offer up any inertia, I felt, created a totally different situation from when I was actually igniting powder and launching a bullet. Not that I'm right and Larry's wrong, but that I did it differently.

So, it happens - primer protrusion happens with light loads and, in my case(s), also increased over the course of multiple firings.

WHY is still in question, assuredly, but enlarging flash holes did change the results in that the primers did not continue to back out/not get reseated.

I did not actually measure case lengths - base to some datum on the shoulder - but who has measured the force of an AR bolt, and in which units would it be quantified? I don't think we have an apples to apples comparison between how much force a primer (pressure in a cylinder) exerts v. the KE or momentum of a bolt closing. Sure doesn't take much to hang one up sometimes. So, that we do not know also.

I think one thing confusing about the quoted comment was that he said headspace "decreased," when he meant increased. I read it a couple times and that part sounded odd to me. Maybe I'm looking at it wrong.

I'm not disagreeing either. I'm not arguing to MY point or trying to convince - still tossing out observations.

I was never convinced the firing pin was affecting headspace, but maybe it does. I still don't know for certain that it's the primer blast doing it, but it makes more sense than the firing pin. Again, I could be wrong. I'm OK with that though, because I found a solution to my problem (not necessarily scientifically), but the the academic nature of the "argument" is good exercise and good fellowship.

 

[Missionary]

So when wondering / pondering fails... get yourself a bunch of proper sized "Rubber O" rings, plop them on the case, and they will hold the case against the bolt head.

 

[popper]

Yes Jeff, the reason I quoted it. Larger flash hole means PP psi decreases faster. Like a cylinder & pison and valve. Long time ago I saw vid comparing brusise(sp) of primers. They throw a lot of hot mass out a long way!! Point I made is how does shoulder setback occur? Gibson claims it's due to primer movement against the bolt. His experiment used the same case many times so I guess it is possible but I don't consider it a problem.
About 20 yrs ago I ran across some gallery load articles, back in the early 1900s when shooting galleries were popular, they used 22 short with the powder removed and bullets swaged smaller in the pump rifles. Eventually they could buy factory gallery loads. Another was the Fins and their 'quiet/secret' training, used wood bullets and primer only rifle loads. IIRC they never sized the brass. Good ammo was scarce.

 

[quicksylver]

can't speak directly to brand but check this out . https://www.artfulbullet.com/index....tol-vs-large-rifle-primers-w-pb-bullets.8026/

 

[Jeff H]

The problem/my concern was not so much a dangerous headspace problem in the normal sense, but the potential for a continuing change in how deeply the firing pin indents the primers each successive firing, up to the point where unreliable ignition would occur. Up to that point, inconsistent ignition from one firing to the next would further contribute to wider-than-desired velocity swings using small amounts of pistol powder.

The hypothesis, as it strikes me is that the smaller flash hole would leave more surface area to be acted upon in the bottom of the primer pocket by the pressure the primer causes, as compared to the smaller area left after drilling. This, ostensibly, would give the primer's force less area to work against in pushing itself out of the pocket. That's the "argument," but while I am familiar with the concepts relative to STATIC pressure, when it comes to what's going on inside that case upon ignition is subject to my imagination, seasoned with some semi-relevant and more limited knowledge/experience with fluids. This is an explanation of how I understand the idea, not an assertion nor a defense. Plausible to me though, I admit.

The Finns,...

If you are talking about these two articles, they are very interesting material to be certain.

Gunwriters' Handloading Subsonic Cartridges, Part 1

Gunwriters' Handloading Subsonic Cartridges, Part 2

I had several other pages bookmarked and in a folder for this topic at one time, but most of the links went dead, which is a shame. I'm glad to see these two still up.

 

[popper]

That was one of them, lost on my old computer. Thanks for finding it.
You are correct, larger flash hole will reduce primer movement in the PP - but after repeated firings of the same case, is the PP still 'normal'? Is it the primer or powder pressure causing the primer movement? No idea!
I sometimes shoot BO with light pistol powder loads, but don't drill the flash holes on any. My solution for non-rimmed would be to fire a standard charge once in a while to get the shoulder pushed back out. That way, no question on being safe for full power loads and no reason to segregate cases. Traded the AR10 for a Henry Long Ranger 308W and haven't shot cast in it much.

 

[Petrol & Powder]

My experience is completely in line with Jeff H.

Prior to the shortages, For handgun ammunition, I mostly used Winchester primers with some Federal stuff on the shelf. This was due to local availability. I did use other brands during that time, usually S&B or CCI but Winchesters carried the lion's share of the load.

Once the shortages became the regular cycle of affairs, I focused on availability and cost. Any semblance of brand loyality was gone. And like Jeff, I can't see the difference. Perhaps it's there and my skill level is below the threshold.

 

[popper]

If you are talking about these two articles, they are very interesting material to be certain.
Yup and the Fin gun regulatons show what happens when a country is regulated!!!

 

[dale2242]

I once did an test using standard and magnum primers in a 45ACP with cast and Bullseye.
Both the standard and magnum large pistol primers were made by CCI.
I fired 10 rounds of each.
I chronographed and shot for group in both cases.
I found no appreciable difference in velocity and groups.
All components were equal except the primers.
Same brand cases, same lot of powder, and same alloy for the bullets.
No a very scientific experiment, but interesting.

 

[richhodg66]

Actually, that sounds very scientific to me, you eliminated a single variable and tested consistently.

There are a lot of times I think we as handloaders are the worst at over thinking. Had a conversation with my brother who shoots Bullseye. He told me the good shooters don't waste time chasing a perfect load. Find a good enough load, make a bunch of them and then practice a lot. The time and energy is better spent on the range than at the press.

 

[Petrol & Powder]

...............There are a lot of times I think we as handloaders are the worst at over thinking. Had a conversation with my brother who shoots Bullseye. He told me the good shooters don't waste time chasing a perfect load. Find a good enough load, make a bunch of them and then practice a lot. The time and energy is better spent on the range than at the press.

/\ Well Said /\