The breech face of my .45 imprints deep grooves in the brass when firing. Spent cases from other pistols I've fired (including a Glock, Taurus revolver, and an XD) do not seem to exhibit this. Does it affect the reloadability of the brass?

Not a problem. Reload till it splits or untill the primers are about to fall out

if reloads cases could be too short or head space off , letting cases move back + slam breech on firing -

if reloads cases could be too short or head space off , letting cases move back + slam breech on firing -

 

How abut too hot a load? Is the primer extruding into the firing pin hole?

No, doesn't look like it. Just a dimple in the primer, no extrusion.

what type of pistol ? - poor machining on breech face ? -

It's a SA Loaded 1911. I'm not entirely sure they are machining marks. Haven't noticed anything else on the gun that might suggest it is cheaply made, then again I've only gone so far as field stripping it.

 

Later today I'll try to grab a pic of it.

on two of the 1911's i have built i had to stone + polish the breech face - i did this before shooting them so i don't know if they would have marked the cases - try putting a new empty case in + rack the slide , see if it leaves marks - if not case is being slammed back on firing -