I'm not real sure about gun stores between here and El Paso. I'm assuming you will be on IH10.
Apache Rifleworks is right on IH10 just before Comfort. They have some really cool stuff, though mostly dealing with hunting, tactical and long range shooting. They were building their inventory of used guns.
Apache Rifleworks ? Custom Tools for Quality Warriors
If nothing else, El Paso Saddlery would be a definite stop.