Apocalyptic Prepping

If you’re having trouble with RCBS or Hornady 300 blackout dies not seating bullets consistently, this should help.

I’m a huge fan of the 300 Blackout round. It’s a fun, lower velocity round that can really pack a punch. In terms of reloading, I also love that it is a 30 caliber round, which I reload for other cartridges, and it can be loaded subsonic. The first time I attempted to load the 300 blk subsonic though I had problems. I was having trouble getting the 300 blackout bullets to seat consistently with my RCBS dies.

I didn’t have any trouble until I tried reloading heavier grain bullets. I was trying to reload 300 blackout with 217 grain projectiles. The 125 grain projectiles I had tried first had worked ok, but those I was seating at 2.080″ OAL which is far below the maximum OAL, and above the minimum OAL with some wiggle room. According to my reloading handbook, that was just fine, and it gave me a little wiggle room to be a little high or a little low.

It was important that I had that wiggle room because as I went back to check, there was some variation in the bullets made from these RCBS dies. The variation in the bullet seating was within a few thousandths of an inch, so it wasn’t crazy, and the variation wasn’t enough to notice until I threw the calipers on it, but I hadn’t ever gotten any variation in my other dies. From my experience and research, this is the list for what you should check if your bullets are not seating consistently-

Trouble Seating Heavier 30 cal. Projectiles

The 217 grain projectiles were even more of an issue. I was using RCBS dies, and I was having trouble getting the 300 blackout projectiles to seat even close consistently. The trouble was, the overall length was different for every single one, noticeably different. As can be seen below, the difference was about an 1/8″. it was pretty extreme. Also, neither of these was the desired OAL I was trying to get.

Crimp Seating Bullets too Deep

I figured that the crimp was catching the bullets and pushing them in further. I figured this out by unscrewing the bullet depth seater all the way up. It was about a full half inch above where it has been, but some bullets kept getting seated deeper, and I could see the markings on the lead projectiles. I did some research and it said that the bullet profile could cause troubles with this brand of die. It seems like an uncommon problem, but the variation I had had with the 125 gr bullets had made me lose faith in the RCBS dies.

I was able to finally start getting bullets to seat reasonably consistently, but without a crimp. I really needed the crimp though, as I was going to be shooting it out of an AR platform. I didn’t want the bullets to get seated too deep when loading and have a catastrophic failure from too much pressure. I needed to separate the seating from the crimp. At this point I wasn’t even suspecting the projectiles themselves.

Separating Bullet Seating from Crimp

All my other dies are Lee dies. Lee is basic, and less expensive than a lot of other options, but that’s what my mentor had taught me on. He used Lee, I learned with Lee, I tried to stick with Lee. I bought a 300 blackout gun at the start of the covid-19 pandemic but couldn’t find ammo, so I knew I’d have to reload it. I had some 300 blackout brass, but I also knew how to convert 223 brass to 300 blk. The stores didn’t have any Lee dies, and Amazon was out at the time, so I went with what the stores had on the shelf- RCBS.

I’d heard good things about RCBS. I’d never heard about trouble with RCBS dies not seating consistently, or having projectiles hung up on the crimp. I hadn’t searched about it though either. It seems I wasn’t the only one having the issue. I also found that people were having the same issues with Hornady dies, which have the seat and crimp 2 in 1 die as well. No issues with Lee. No issues with Dillon. No issues with Redding. Of those, Lee was what I was used to, and what was in my budget.

Converting 204 Ruger Brass into 300 AAC Blackout

Using Lee Dies

I bought me a set of Lee dies and loaded up a batch. It all loaded up perfectly. I measured my first 10 out of the press, and then every other one for the next 20 after that. The consistency was on point. No issues. I was able to then crimp separately and got a good clean crimp without messing with the bullet depth. The overall length met the specifications and I was in business.

It turned out that my main problem with the 300 blackout bullets not seating consistently was my projectile itself. After I was able to successfully load up some 217 grain 300 blackout bullets with the Lee dies, I then went to test them but couldn’t even chamber them.

The picture below shows the result. The damage to the tip was from me having to mortar them out of the gun.

What bullets were out of spec?

I was using Gallant 217 grain bullets. I don’t want to bad mouth them too much though, because they made the situation right. I emailed Gallant bullets, the manufacturer and they handled it like pros, see the email below:

Hello,
We take responsibility for your .30Cal 217gr BT bullet issues outlined in your email. We had a sizing die wear out and a number of these made it out of our facility. Let me know how many you have, your shipping address, and phone number and we will email a return USPS label to have these returned and ship you some replacements at no cost to you.
Shem Fischer
Director

Things to Check if Your Bullet isn’t Seating Properly

• Check to make sure your projectiles are in spec
• Check to make sure your dies are clean
• Seat the bullet and crimp in 2 separate steps

I kept the RCBS dies because I like the sizing die for when I make 300 blackout cases. I really like sizing the case before I cut it. It just works.

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