I just loaded 50 rounds of Hornady XTP .45 Cal 230 Grain using No. 7 powder.  I brought them to the range today to shoot in my Sig Scorpian 1911.  First round in a mag would chamber and fire fine, second round would chamber but the slide wouldn't close fully.  I'd drop the mag, clear the round, put the round back in the mag, put mag back in the Sig, rack the slide and fire.  Again the next round would chamber but the slide wouldn't close completely.  I checked the OAL on the rounds and they were solid at 1.25, so not too long.  I had just shot 80 rounds of 230 grain BVA reloads without an issue.  Any ideas?   

I'd check your OAL again.  For my 45ACP, I'm usually loading to about 1.20 or 1.22.  While that seems very short, that's the recommend OAL for the powder I use, Titegroup.  Another thing, is to make sure your crimp is tight enough.  As mentioned above, it could snag on the shoulder a little bit.

You can probably test it out on like 2-3 rounds just to see if it will fit.  You don't necessarily have to go to the range.  What I do, with finger off the trigger, is pull the slide and let it slam back.  The round should load and the slide lock forward.  If it doesn't, pull the slide back so it ejects the round and let the slide slam forward again, loading the next round.  See if it loads again.  Make adjustments and repeat.

But with anything, make sure your firearm is pointed in a safe direction in case you get a slam fire.  I always do mine in the basement in my cold storage room with ear plugs.

My brother in law had the same issue with his scorpion 1911. Although he wasn't shooting reloaded rounds and it would only happen every few rounds. He was shooting Remington 230gr hollow points straight out of the box. Any ideas? Does he need to just break it in first? Or has other people had the same issue with sig other than us?

Hmmmm.  I don't know what to say.  You could always give them to me and I can shoot them for you.

OAL had always been the solution for me.

what you can aslo try is to pick up a case gage and check your cases sometime when you size them like with rcbs dies it creates a small bulge at the rim so the shell will not chamber, lee makes a bulge buster die and kit that will fix the bulge on the cases you can even put a loaded bullet through it i have not had this problem with my 45's but i have with my 40's the chamber in my px4 is so tight i have to use the bulge buster die on about half of my reloads.

So what was your final OAL?   I think many loading manuals are 1.20

My Les Baer has a very tight chamber, so I've found that if I don't run my reloads through a Lee Factory Crimp Die they will occasionally have a tough time chambering reliably. The Lee FCDs are cheap insurance...