I have been loading some reduced loads for my new 9mm to see how low I can take the loads to reduce recoil for faster follow up shots. I also built an 8 x 8 foot sheet hanger to catch my brass. I went to the range today to test it out. It is a series of four foot lengths of 1 1/2" PVC pipe and connectors with a king size sheet hung from the top rail. I loaded a magazine with factory ammo first and the gun cycled as always and the brass catcher collected all the brass in a circle about 2 feet in diameter. Good job, I told myself and nearly strained my arm patting myself on the back. Then I loaded the first five reduced loads at 4.4 grains of Titegroup with a 115 grain bullet at the advertised OAL.. I let the slide go forward and aimed the gun while squeezing off the first round. Hmmmmm, the hammer fell but there was no bang and no recoil. I waited the 30 seconds keeping the gun pointed down range with no bank. I dropped the magazine, and tried to work the slide... Locked up solid and I noticed it was not fully in battery. I thought the primer had gone off pushing the bullet into the bore but not enough to clear the case. So I put the lower front of the slide on the bench and pushed it hard. The slide came back and I picked up the brass that had ejected onto the ground. I ran the slide back and locked it in the open position to notice the gun had unburnt powder all over the place. I couldn't gert a clear view of the bore so I quickly fied stripped the gun and sure enough there was a bullet lodged in the bore. I got a couple of tools out of the range box and gently tapped the stuck bullet out. There was a strike vacancy of any charred powder or primer residue so I looked at the case and primer. The primer was untouched. I lined another reload next to a factory round and they were the same height but different types of bullets. I chambered the factory round with no problem so I chambered another reload. Same problem and I hadn't even pulled the trigger. I had the same stuck slide and when I forced it open the bullet remained in the bore.
All my reloads were long enough that the bullet was getting wedged into the rifling trying to chamber. I took down my fantastic brass catcher and bundled it up to put it back in the trunk and went home and re- reloaded two hundred rounds after checking the seating length to make sure it would chamber. So, I may get to go back to the range tomorrow to test My reduced loads. I will remember to check the bullets in the chamber before loading the second one from now on.
I double checked and the book lists 1.169" for OAL and I need to load them to 1.032" OAL to get them to chamber. Each of my manuals have different seating depths from 1.169 down to 1.090". From now on I check to see if they chamber.

never too old to learn...
and speed is a bad teacher...

15 minutes of thinking and planning will save you about 3 hours work...

I was blessed with a mother who had lots of such advices (and with most of them I didn't agree... at that time... but now that I'm a grandfather myself...)

so: no harm done (except maybe your ego )
and all's well that ends well.

Ran into similar issue with 147gr. bullets !!!
Turns out the chamber in my XD is different than my other 9's

Word of caution. ..... setting the bullet back on 9's will quickly affect pressures.
I've found in order to make power factor for IDPA the the 147gr bullets work better than the 115's in controlling muzzle flip.

200 rounds!!!!! isnt this a load development??????
5 of this aand 5 of that till you have sweet spot...THEN do the 200.......if you get to range and they group like a scattergun you have 200 to blast off or pull.
and Ive been caught with my .270 and 170 grn pills that were too long for mag......

Paul, I ran into the same problem with my 9mm loads. All 124-125 grain bullets, same OAL but some were plated, some cast. All would run through my Ruger but the XDs and CZ P01 both choked on the cast loads. I haven't measured them but can see that the shoulder on the cast bullets is farther forward than on the plated bullets. The sad part is that I checked to see if they would chamber, in the Ruger... Then I loaded 500 of them...

I am working loads down to check function. I don't think I have to worry about pressure in these loads starting at .1 grain below "starting" load and going down in .1 grain steps to what I figure should stop the gun from functioning but not cause any squib loads. Once I find the minimum functioning point I will do the load work up. I loaded 10 of each load and it was just one hundred but I had to pull the bullets and the reload 100 bullets - that's why I said two hundred.

I haven't gotten back out ti the range yet but tomorrow looks like a good day.