The most bang for the buck when function checking

OK, I got a new magazine or two and I want to make sure I can depend on them so it’s off to the range for function checks.

I want to conduct the function checks with my JHP SD ammo for obvious reasons.
My JHP SD ammo currently is irreplaceable and I’m down to my last few boxes, but I"ve still plenty of FMJ and range ammo, however how my pistol will act with these new magazines loaded with JHPs is obviously my bigger concern.
So I’m thinking, which sort of training exercise should I use to run these new magazines through their paces?
I’m limited to an indoor range since local wildfires have shut down my only available outdoor range until further notice.


Well nothing EVER beats range time, however…

Realize that every time you load a round into a pistol and it strikes the feed ramp it will almost certainly set the boolit back in the case a bit.

For magazine function to be even close to comparable the slide must be cycled at a high velocity. The problem with that is our grubby fingers like to grab onto things when we are doing things quickly and sometimes that can be a trigger.

You didn’t mention what type of firearm you have but here are a few options
a: If you have room behind the trigger, put a bolt and a nut behind the trigger, tape it in place
b: If you can remove the firing pin, do so.
c: If you cannot physically disable your firearm, wrap electrical tape from the grip over the trigger around the trigger guard until there is no way you can get to the trigger.

Pull however many rounds you need to fill a magazine.
Measure each one to ensure that they are just about the same length. Write that measurement down.
Now take the full magazine of your FMJ and cycle them manually through the new magazine as fast and violent as you can.
Measure each round to ensure it has not shrunk more than 1/16th of an inch (a$$uMEing 9mm)
Continue until the boolit set back is 1/16" or less, put those rounds into the range ammo box.
Repeat as needed to make you confident in the magazine function.
Remove all stops and such / install parts to return the firearm to working order.

Go to the range load 1 set back round and one JHP alternately for the duration of the mag and send them. If they gobble them up you are good. If you have FTFeed/FTFire pay attention to what round is causing the issue and evaluate. Also evaluate if it is at a certain point in the mag where things happen. Test with your FMJ and check with your JHP’s. All FMJ except the last 3 . First 3 JHP and a mag full of FMJ. FMJ 3JHP and the rest FMJ. If it passes these last three tests you are golden for the cost of very few of your JHP’s.




If you have used your JHP ammo in your pistol with no issues, I would just check the mag function with target ammo. If one of them is faulty, it will be faulty with the target ammo as well.


I think the only thing you can do, without actually firing it, is as @Craig6 suggests and that is load a magazine and manually cycle it.

You must be VERY CAREFUL to keep your finger out of the trigger area if you can’t physically disable it.

I would keep an eye on bullet setback, racking it once or twice is usually not an issue, but I wouldn’t make this a habit and again as @Craig6 suggests take a before and after measurement if for nothing else than your peace of mind that you don’t have any setback issues.

What firearm is it and what ammo is it? If it’s something like a Glock and Federal HSTs (just one example) there are a bajillion people running that combo so it’s very likely a safe combo.

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You mentioned two different things. Testing magazines and not using your carry ammo to do it.

You should be able to tell if the bullet geometry of your carry ammo is an issue with the magazine design though close visual inspection and observation (too long, snags on path of travel, etc)

I expect the main concerns of verifying the magazines are feed/retention lips adequately retain rounds prior to feeding, operation at maximum spring pressure, and operation at minimum spring pressure. Range ammo should be largely acceptable for this. Someone please correct me if for some reason you know this to be wrong.

In the end, you will never get complete peace of mind without actually verifying the intended combination under operating conditions. 3-5 rounds from your limited stash is still cheap insurance when it comes to your life.

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I think i misread the initial post. If you know this SD ammo works in your firearm well (JHP and your feed ramps get along nicely) and its just testing the magazines, then yes I think largely just using range ammo should be GTG.

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My 1911 functions reliably with Winchester JHP from my CheckMates. What I want to know is, will mine be as reliable with an 8 rd Chip McCormick Match magazine with a 9th JHP up the spout.

I had to ask myself, is and extra ten bucks/magazine really worth having an extra round?
I’m guessing, if it came down to it, is yes if it is reliable.