You will now and then read of a reloader or a competition shooter who only loads in new or once-fired brass. Why would they do that? And what's wrong with mixed brass, even range pickups? Simple: consistency. They want all their brass to be matched, so they can obtain the gilt-edged accuracy they desire. The question we all have to ask is, does it matter? And if it does, by how much?
To test this, I selected a Les Baer Heavyweight Monolith 1911 in .45 ACP, a Ransom Rest and one of my go-to loads: an Oregon Trails 200-grain lead semi-wadcutter and a charge of VihtaVouri N-310. It's a brilliantly accurate load. For a jacketed load, I went with Hornady's excellent XTP in 200 grains and WW-231 powder.
I have gallons and gallons of much-used .45 ACP brass, so I simply pulled the first bin off the shelf. My mixed-brass bins are simply various brands, headstamps and number of firings brass—inspected for cracks or other defects. For new brass, I used unfired brass from Starline.
The process was simple. I loaded 50 rounds of the Oregon Trails load into the used, mixed cases. Without changing anything I then loaded 25 rounds in the brand-new Starline cases. I swapped the bullet seater for the XTPs, changed to WW-231, and repeated. Fifty rounds of XTP in used cases, then 25 in new.
The process was simple. I set up the Ransom Rest on a heavy shooting bench at the club, got the Monolith seated and aimed and started checking point of impact and consistency. Once I had it reasonably centered on the target, and the groups seemed settled down (it takes a while for Ransom Rest inserts to get settled), I proceeded to use the mixed-brass lead bullet load for additional settling and bore-conditioning. I then used the last 25 rounds of that for record, measuring five five-shot groups. With everything settled in nicely, I used the Starline brass ammo and recorded five five-shot groups of that.
Then, since the Monolith was on paper, I changed to some conditioning ammo that also used Hornady XTPs and WW-231. After 25 rounds of that, I shot the remaining 25 rounds I'd handloaded for record, measuring five five-shot groups. Then repeated the recording with the 25 rounds of Starline brass and the Hornady XTPs.
The results, after all this work, will be underwhelming to some. The new Starline brass shaved only an average of 0.3 inch off of the groups at 25 yards. That, however, can be a big deal to a competition shooter. At 50 yards, that is half an inch, and that can mean points kept, that would have otherwise been lost, if the groups had been larger.
The Hornady load managed even less of an improvement, but look where it started. The mixed-brass XTP load was shooting just barely over an inch at 25 yards, and making those groups tighter is pretty difficult.
What was more interesting were the velocities. The velocities for both were higher with the new brass, and they were more consistent as well. For a shooter who has to meet a power level, the smaller deviations in velocity means they are better-protected from an errant round pulling them below the threshold. I once shot a big match once with ammunition that fell ever so slightly below Major, and spent the week shooting a Major-recoiling handgun but getting scored Minor. Trust me, it was not fun.
For the serious competitor, anything that avoids losing points is a technical detail to have. Improved accuracy, more consistent velocity, these are things that matter when the gap between winning and placing second is a small percentage of the overall performance.
There's also the incalculable advantage of confidence. Knowing that new brass is going to deliver the best possible performance boosts your mental performance. In other words, if you think it helps, it probably does.
Now, what is the cost of this advantage? At the moment, used brass costs whatever it takes to pick it up at the gun club. And if you shoot and reload long enough, you too will have gallons of mixed brass. Starline .45 ACP brass, at the moment, costs $165 per 1,000 rounds. So, it is a question you and your wallet have to answer. As much as I like and respect the folks at Starline, for a lot of shooters, that $165 is probably better spent, at the moment, on more bullets, powder and primers.