Doing some initial shopping at MIDWAY USA and notice that they classify their handgun primers by "large pistol" and "small pistol". I was surprised to find, when reading reviews about the small primers, that some said they used them in .45 ACP. That lead me to believe that the difference between "large" and "small" was not about the caliber of gun.

Would someone please educate me on this?

By the way, in the "large" category, they have none on hand are are not backordering. In the "small" category they have these http://www.midwayusa.com/viewProduct/?productNumber=568829in stock for $30.00 per 1000. They seem to get good reviews so that is what I'll order, but I'm still curious about the large and small issue.

Thanks,
Craig

There is two different sizes in primers. Small and large. Then you have two catagories in that of regularand magnum.

45ACP, 44mag, 45 colt, etc all use large pistol (magnum for slow burners like H110)
9mm, 40S&W, 357sig, 38spl all use small pistol
357sig, uses small magnum primer.
Then you get oddballs like 460Smith that uses large rifle.

I don't think you can put smal pistol in a 45ACP unless the brass allows it. I do know some brass will allow it. I buy starline usually and they only allow large pistol.

It has to do with how the reviews are written. You might find a review for a .30 cal bullet "yeah I shot these in my .338 Federal and they suck"

At first glance you'd think no wonder, but the reviewer is not writing his review for the correct item. One guy who shoots ballistic tips in his .243 may write his review under the .22 caliber ballistic tips.

In other words, the reviewer had the brand right, but not the correct size.

I'd bet this is what happened.

.45ACP NT uses SP primers NT Non Toxic.