- fixed the railgun's spiral duration was set incorrectly.

src/p_effect.cpp

@@ -764,7 +764,7 @@ void P_DrawRailTrail(AActor *source, TArray<SPortalHit> &portalhits, int color1,
 			int spiralduration = (duration == 0) ? 35 : duration;
 
 			p->alpha = 1.f;
-			p->ttl = duration;
+			p->ttl = spiralduration;
 			p->fadestep = FADEFROMTTL(spiralduration);
 			p->size = 3;
 			p->bright = fullbright;