9mm break in ammo?

My Glock 26 had issues with 115gr initially (5+ FTE), so I shot 124gr on my second range visit. I think the issue had more to do with the tight magazines, so all three were left loaded in between trips. Two of them were hard to load more than eight rounds out of the box. I haven't had a single issue since then, and have put many more boxes of 115gr through it.

I don't necessarily buy into the whole break in process for handguns, but I do ensure a gun is reliable prior to carrying. To me that includes the whole package (gun, magazines, ammo). Any modern semi auto should be able to shoot any factory ammo in that caliber, excluding the higher pressure rounds that are sometimes discouraged by manufactorers. But if I'm having issues with one brand I will change it up before declaring the gun a total loss.
 
Break in is silly. Shooting a few hundred rounds to test for reliabity and assurance against factory defects is common sense.
 
^Silly, except in those instances where the manufacturer requires a break-in period.

It was pointed out in a thread devoted to proving your chosen defensive round in your pistol that each cartridge-magazine-pistol-person system is unique and must be proved separately. You can calculate the required sample size per lot of ammo as:

n = ln(alpha)/ln(coverage)

where:

- n is the required sample size (round the result up to the next integer);
- alpha is the false-negative error rate, traditionally set at 0.05 if you wish to be 95% confident in your results; and,
- coverage is the minimum level of reliability you are willing to accept (I've opted for 0.95, or 95%).

For example:

n = ln(0.05)/ln(0.95) = 59.

Thus, after firing 59 rounds of my chosen defensive round without failures with each magazine I can be 95% certain that each cartridge-mag-pistol-me combo is at least 95% reliable. If my carry round of choice were particularly expensive, I'd likely use:

n = ln(0.05)/ln(0.90) = 29,

where with 29 failure-free rounds per system combo I could be 95% confident of 90% reliability.
 
You're willing to stake your life on being wrong no more than one time in TWENTY, that your firearm will malfunction no more than one shot in TEN?

I want better odds than that.
 
You're willing to stake your life on being wrong no more than one time in TWENTY, that your firearm will malfunction no more than one shot in TEN?
Click to expand...

I said I am willing to stake my life on a system proven, with 95% confidence, to be at least 95% reliable. That means firing 59 rounds with no failure through each of the three mags I have for each pistol.

Note that the supposed best estimate of reliability of a system proven with 59 successed out of 59 trials is:

p = 59/59 = 1.00

or 100%. Given the uncertainty inherent in any sampling scheme, and the fact that no mechanical system is 100% reliable, I prefer to use the LaPlace method to obtain the best estimate of reliability:

n = (59+1)/(59+2) = 0.98.

Thus, a 59-round test of a cartridge-mag-pistol-me system conducted without any failures tells me the system is about 98% reliable while being at least 95% reliable with 95% confidence.

I, too, would like to be more certain. For example, I'd like to be 99.9% confident that each system is at least 99.9% reliable. But:

n = ln(0.001)/ln(0.999) = 6,905.

My budget does not allow me to obtain 3(6,905) rounds of premium JHPs to prove each of my mag-pistol systems reliable to an idealistic level. Besides, even if I had the money, time, and stamina to conduct a set of reliability tests involving more than 20,000 rounds, what systems would be proven reliable at the conclusion? I'd have been replacing parts long before the tests were done.

I'm capable of being an idealist, but I allow reality to intervene and set reasonable goals.

By the way, the best price I can find for Federal Premium Tactical 147-gr HST is $0.60/round. For my chosen reliability testing protocol (assuming no failures) I need:

3(59 rounds)($0.60/round) = $106.20

worth of ammo. The idealist scenario requires:

3(6,905 rounds)($0.60) = $12,429

worth of ammo.

I presented the formula so folks can use whatever values of confidence and coverage (minimum reliability) they wish to use. I've crunched numerous sets of values and settled on 95% confidence and 95% coverage. This experience is why I said I would ease my ideals further to 95%/90% under conditions where ammo was more expensive, as post-Newtown when premium JHPs were going for well over $1/round.
 
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I've "broken in" 3 9mm pistols. Other than a minor mag tweaking on the first one, they have all performed flawlessly on 115 gr. I cleaned, lubed and shot them. I didn't do any polishing or tweaking since they all shoot well. I don't know why my RIA 1911 called for a 500 round break-in since it shot great from the first round.
 
I'm going to do a reliability check starting with 147 gr, 124r and finish with 115 gr.
Just for the heck of it and because I have the ammo may as well make sure all the magazines like the choice of ammo just in case.
I'll also run some 120 cast reloads thru them last its been good thru my BHP.
 
I can't imagine carrying a gun without a few hundred rounds, including at least a few magazines of my selected carry ammunition run through it.

Kahr dictates a break in. My T9 needed it. I just used WWB for the majority of it. I would guess manually cycling the slide repeatedly would help with the break in a little, although it wouldn't totally replace firing live rounds.
 
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