You can check the size of the barrel easily from the muzzle...
http://forum.lugerforum.com/showthre...ghlight=pencil
These Lugers in original condition are sought after and somewhat valuable as collectibles.
If it's all matching and in original condition, most collectors would not fire it for fear of breaking a numbered part. One that is more rare would be collectible with a mis-numbered take down lever.
You bought this well below it's market price.
Marc
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.