IMO if the gun is new or new to you I would shoot about 500 rds (FMJ) in it, then run a box or two of your carry ammo.

Generally 500 rounds is a pretty accepted "break in" period. Be sure to shoot some of your SD/HD ammo too as the POA/POI may differ. Especially if the JHP's are a different weight than your FMJ's (typically they are). How the weight difference affects where the bullet will strike is important to know so that any adjustments on your end can be taken into account before pulling the trigger. It'll also develop the muscle memory for the difference in recoil as well.

Originally Posted by azncheeta08

How many rounds should I put through the gun with the hollow point ammo before I should consider it reliable/compatible with the gun?

As many as it takes to gain your confidence.

I usually throw 100 or so of the JHP I plan on carrying downrange when I change what I carry. Then I'll throw another 100 or so more downrange every 6 months or so just to circulate the inventory. Sometimes I'll do it more often.

I won't feel comfortable carrying a pistol until it has three or four hundred rounds through it without any failures of any type. This will include at least 100 rounds of carry ammo.

Since you have a Glock, you can shoot just about any ammo out there....

PhilR.

Thanks for the answers everyone, I'm heading to the range tomorrow to fire some JHP. I'll probably just swing by Walmart or Dicks to pick up the ammo. Does it matter whether I break the gun in with FMJ or JHP??

Originally Posted by azncheeta08

Does it matter whether I break the gun in with FMJ or JHP??

No. Though generally the FMJ's are more plentiful for the price so most go with them first. Up to you really, though. Have a good shoot.

Try out a mag or two of whatever you plan to carry to me sure it's going to feed and cycle OK. Most times the first round or two in a mag is where you are going to see it hang up if it's going to. Well..The first 2 and the last one.

As unpecador said..As many as you need to feel confident.

Most all ball ammo will feed well..Especially in a Glock, But it's always good to run some through it just to knock the new off of it and get you where you feel OK about the over all feel. Then send some HPs through it so you know that the ones you have will feed OK and you can see if your gun likes them. Some guns while they will eat it that don't mean they will group well. So it's a good thing to get a few different kinds and see what it likes. I've yet to see a Glock that didn't like the good ole Hydroshok Federals though.

I use winchester ranger T 9mm in the 124gr +P variety. ive conducted gelatin tests with it severazl years ago as well as the 127gr +P+ and the former does very well with penetration and expansion. the expansion betwee the 124 an d 127 is almost the same (many were the same), and the 127 penetrates a tad better. but, the 124 kicks way less and is also easier to get. Its a great choice, but so is speer gold dot. good luck and choose well.