Pressure signs on primers

[M-Tecs]

A friend of my dads took the top strap and top three cylinders off an 1873 Colt 45 colt clone with a Ruger only load. The case head stayed in the cylinder. Primer looked fine.

[44MAG#1]

A friend of my dads took the top strap and top three cylinders off an 1873 Colt 45 colt clone with a Ruger only load. The case head stayed in the cylinder. Primer looked fine.

Did he not see where the data was listed as a RUGER ONLY LOAD?
On loading data I try to read and absorb all pertinent info

[TurnipEaterDown]

Agree 100% with the higher pressure loads in rifles. Reading the primer provides valuable information. In low pressure loads like 45 Colt at 14,000 PSI or under not so much. Same for lower pressure semi-autos loads. Most handgun primers don't start showing actual pressure indicators until above 40,000 PSI. In rifles that about 65,000 PSI. Your 1873 first gen Colt and your 1873 trapdoor will be in pieces long before you get "pressure indicators" from your primer.

Both of my Sig 365 XL's have fairly heavy firing pin drag marks. They are both 100% reliable and I could care less about the drag markets.

This is what I do too on higher pressure rifle rounds where I have little to go on -- i.e. wildcats, surplus powders, etc.

Fire some known loadings of powder & bullet (manual or reliable wildcat data) and work up to Max identified. This has assumptions baked in, but Generally conservative.

Measure case length to shoulder accurately. Comparator w/ insert that mates to shoulder works OK.
Record velocity, charge, calculate energy, and changes in velocity and energy per charge weight change.
Look at the primer of published loadings for That One Gun under a magnifier (I use a pocket loupe) for characteristics such as the width of the flattened area of primer face (annulus), presence & "definition" of machining marks from bolt face transposed to primer face, presence & "definition" of defects from bolt face like pits transferring as bumps on primer, sharpness of transition from edge of primer face to firing pin indent, finish of the firing pin indent on fired primer (i.e. does the surface of the indent look like an unfired primer face or is it Very smooth & shiny, can metal shearing been seen in the pin indent, etc.), and the transition from the tip of the firing pin indent to the "walls" of the firing pin indent. Basically, look for Changes in Any Surface feature of the fired primer across the incremental charges of known/published "safe" loadings, and be cognizant of all these characteristics at the max loading.

Change powder Or bullet, etc. to unknown / unpublished component in load. One thing at a time.
Run incremental powder test on best judgement for charge range, look at velocity during shooting, and look at the primer appearance in detail as best I can as above at the range and every fired case at home. Also look at case length change (never found this too useful on front lug bolt guns, but have recently on Lever guns).

Work up to energy limit established as above in "known" section IF none of the primer deformation signs on the "unknown" load exceeds the signs seen on the "known" load, and the case length change doesn't exceed the "known" loading(s).

Look at energy per charge weight to understand if the powder is still acting as expected (when using a Surplus powder, or a canister powder in a wildcat).

In the case of surplus powder, I also try to keep my "experimenting" to guns of high strength margin until I believe (personal risk judgement, may not apply to any other person) that I understand the characteristics enough to move to something more "risky" like compounding factors 2 or 3 at a time (transfer use to a wildcat w/ a unpublished bullet, etc.).

Obviously this applies to One Gun at at time as the "primer signs" are all about how the deformation of the primer appears in the unknown load versus the same fixed physical constraint system with a "known" load. If a different gun is used the machining finish and profile of all these mating parts changes, so irrational to expect the same "signs" from a different firearm -- the parts are different.
I think this also works OK, as in a bolt gun w/ properly sized brass, nothing should be moving to any appreciable degree except the firing pin.

Several older sources suggest measuring case head expansion with a blade mic, so years ago I got one.
I never use it much though, as the people proposing this method seem to disagree on things like expansion limit, case prep, case condition (new, once fired, and multiple firings), and so it seems hard to get a "guardrail" if you will.
I did measure case heads for a while, and did see the 0.001 - 0.0015" change on loads that produced other (obvious) pressure signs like ejector slot / plunger marks, but I figure if I saw that I would have known to back down to an estimated reduction in pressure by 10% anyway (bolt gun guideline for Me -- start to see EJ marking, safe pressure was about 10% behind ya).

[charlie b]

There can be a lot of primer 'movement' even in lower pressure loads.

I don't much pay attention unless I have some good references for that specific primer (mfg and type) and that cartridge in that specific weapon. Yes, I can fire, eg a 9mm, in one pistol and everything looks fine. In another pistol the primer looks cratered and another it will be flattened a bit more. That specific case was done with factory ammo.

[racepres]

There can be a lot of primer 'movement' even in lower pressure loads.

I don't much pay attention unless I have some good references for that specific primer (mfg and type) and that cartridge in that specific weapon. Yes, I can fire, eg a 9mm, in one pistol and everything looks fine. In another pistol the primer looks cratered and another it will be flattened a bit more. That specific case was done with factory ammo.

Maybe true, maybe Not, that powder Burn speed attributes to "drag" at primer... Since I do Not prefer "Self Shuckers" ...IDK

[mattd]

I don't have any primer drag. Unless that scalloping can qualify. However, the scalloping isn't touching the firing pin dent. If it is dragging, it would almost be like it made square/even contact, the pin recoiled back, and as the case was ejecting it recoiled forward and took a scoop out, off center.

I do have reference rounds. The 15 cases on the right in the original pic are the same primers, gun, etc. Nothing weird there. The others are the particular load in question, but range from min to max in the Lee manual. All show cratering and/or other markings.

That manual doesn't show pressure at min, but at max it shows as 19600 psi. For the 15 cases on the right, 5.5g W231, that Lee manual shows 5.6g of 231 at 16900 cup. An internet conversion calculator shows that's only 7700p psi.

So, is the consensus that I'm safe to continue with this loading? Are there solutions to keep it from happening?

[dverna]

Interesting thread. It has convinced me I have one year of experience....in the 50 years I have been reloading.

I cannot answer the question posed by the OP. Really puzzling as he is using published loads.

I never worried about pressure in pistol loads but never reloaded anything exotic. .380, .38/.357, 9mm, 40 S&W, ..44 Mag, 45 ACP, and .45LC. Never loaded anything at maximum and used canister powders that I had data for. Pretty mundane life.

Good point made about how a primer cannot tell if it is in a 20k or 40k cartridge. Seems “reading” primers on .38 Spl or .45 ACP loads is not a good way to evaluate load safety.

[35remington]

As long as the pistol functions normally and velocities are within the normal range the “solution to keep it from happening” is to recognize it as the insignificant thing it actually is and get on with it.

Internet “conversions” of psi to cup are totally and completely invalid. Do not use them….total garbage.

[mattd]

Shot a few more at the upper end. Loaded .005 longer. half were Win LPP, half the same CCIs as before.

The Win primers showed nothing weird. Shot those first and figured the longer length had solved it.

The CCIs showed the same as before. No firing pin mark, scalloping, etc.

So I guess that removes primer drag and the firing pin from the equation? If so, Having a hard time wrapping my head around why the CCI works great in 44 mag and flows so much in 45 acp.

[FISH4BUGS]

apparently...the way we have been using primers as pressure indicaters for years "is all wrong" and doesnt work...according to many out there now...you "just have to use a chronograph" and plot curves on a graph and look for flat spots and drops in velocity or your just an old fashioned fuddy duddy who knows nothing....apparently.

Gosh...I will need to start seeing my therapist again. The crushing knowledge that I have been doing this all wrong for 40+ years is depressing.

[josper]

I just bought an accurate mold 45-200H .its a clone of the H&G 68. I had no idea what the OAL is supposed to be. I set it so the case mouth was just even with the top band on the bullet. it was 1.211 as I recall. what did you come up with and how?? Reply to "mostlyleverguns"

[44MAG#1]

When I load the H&G 68 I use 1.250 OAL. Works fine. Don't pay attention to primers myself probably 90 percent of the time.