IF you drop in a caliber conversion barrel-- any pressure issues?  IIRC there were some issues awhile back with this/...

What caliber conversion specifically do you speak?  45 to 10, 40/357 to 9, 45 to 45 Super etc etc?

Looking the 40 to 9--I have a 35.

No issues at all.  I personally like KKM but plenty of people have had good luck with wolf. I have tried wolf and had issues with my reloads but it ran fine with factory loads. I have a Storm lake that has had zero hiccups with about 1200 rounds though it and two KKMs that have had zero problems as well.  I have never ran one in a G35 but I run them on a G22 and  G23.  Stick to a quality barrel and you will be good to go.

Easy and the most common conversion.  My G32 I had to swap the ejector.

Got a Lone Wolf for my G35 several years ago along with 9mm magazines but left everything else stock. Sometimes change calibers on the fly during the same range visit.. Seems to run all the FMJ I've tried but one which caused a challenging jam. The rounds wouldn't chamber, but the slide went forward just enough that the round wouldn't fall out the empty magwell. Nor would the slide move more than a millimeter either way. Took several minutes of shaking and banging before it fell out. The jam happened three times in a row with the same ammo, so I burned up the rest of it through my Sig P228. It reliably feeds Winchester, American Eagle, Magtech and PRVI Partisan, 115s, 124s and 147s of these brands. Use the G35 in 9 mm as a target and competition pistol. Change it back to bone stock .40 S&W for home defense.

More recently got a Double Diamond conversion on discount from The Glockstore for my G22. Seems to run all the same stuff mentioned above, but haven't put more than a few hundred through it. Again changed only the barrel and magazines. The G35 has handled almost 3,000 rounds of 9mm FMJ reliably except for the three rounds of the one brand. Both barrels worked as straight drop ins, no fiddling or smithing needed. Several of the more expensive ones I considered come with the warning some fitting may be needed. Didn't want to have to deal with that. Finally, both were very accurate.

Thanks for the replies--I got the 35 Blue labeled and since my last thumb surgery have had issues...

KKM is the way to go.

After wrist surgery last year, i completely understand recoil tolerance. 300/400 rounds of 9mm earlier today has me hurting tonight.

Kkm is the best, lone wolf works also

got a lone wolf conv barrel for a 23 and it works great even with the 23 mags i do use the 19s all the time but every now and then i load them up they feed just fine.going to get a sig 357 barrel and try that also.

FYI, won't last long but S3F has some 22 and 23 threaded conversion barrels for $117 shipped.

Thanks, but I live in California!

No pressure issues.  .40 and 9mm operate at similar pressures also a 9mm conversion barrel has to fit where the .40 barrel was so it will be thicker than the 9mm barrel otherwise would have been.  Even more pressure tolerance.

Going from a larger cal to a smaller should be no issue due to the extra barrel material.  If it's for carry I suggest changing the extractor and ejector to 9mm also.  Should work without but it's extra insurance.

There are unthreaded barrels available at the same price