300 BO subsonic reloads

[BAgun]

I've recently started reloading 300bo subsonic. I'm using 10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers. It seems that every once in awhile a round won't fire. I've only made a few at a time then test it out. I just had one not fire and manually ejected it, it didn't even look like the primer was hit. I put it back in and then it fired. I was just seeing if anyone had similar issues or advice on how to fix this. Thanks for any help.

 

[edwea]

Is this in an AR? Even just chambering a round in the ar usually dimples the primer.

 

[turnerdye1]

Yeah sounds like it may be a bolt problem and not the rounds itself. Unless those rounds have extremely hard primers

 

[BAgun]

It's in an AR platform. I was thinking about putting in knew firing pins, see if that would help?

 

[bobjones223]

How are you loading the AR?

If you are testing rounds is there a chance you are hand feeding them and easing the bolt into place instead of letting it slam forward?

Am I right?

 

[BAgun]

How are you loading the AR?

If you are testing rounds is there a chance you are hand feeding them and easing the bolt into place instead of letting it slam forward?

Am I right?

I'll double check but I'm pretty sure I'm just letting it slide forward.

 

[bobjones223]

I'll double check but I'm pretty sure I'm just letting it slide forward.

Have you tried it with a box of factory ammo? If it runs fine on store bought it is the ammo. If the same problem continues with factory ammo it is something in the gun.

 

[BAgun]

Have you tried it with a box of factory ammo? If it runs fine on store bought it is the ammo. If the same problem continues with factory ammo it is something in the gun.

I've not had any issue with store bought ammo. I'm assuming it's something I'm doing, just can't figure it out yet.

 

[AndreusMaximus]

Is this in an AR? Even just chambering a round in the ar usually dimples the primer.

How are you loading the AR?

If you are testing rounds is there a chance you are hand feeding them and easing the bolt into place instead of letting it slam forward?

Am I right?

^^^This.

If you aren't seeing even the slightest dimple on the primer, the most likely case seems to me to be that the bolt isn't going fully into battery. If the bolt isn't all the way forward, then when you pull the trigger the hammer will smack on the back of the bolt, so you'll hear a "click", but the firing pin won't actually be able to reach the primer, and the round will be completely untouched.

I've had issues with my own reloads before where either due to the brass not being sized properly, or the bullet being seated too far forward, it wouldn't go fully into battery. If you're not having any issues with factory ammo, I'd say this might be your problem, though I would think you'd definitely notice it being a lot harder to pull the bolt back and get the faulty round out of the chamber.

 

[BAgun]

^^^This.

If you aren't seeing even the slightest dimple on the primer, the most likely case seems to me to be that the bolt isn't going fully into battery. If the bolt isn't all the way forward, then when you pull the trigger the hammer will smack on the back of the bolt, so you'll hear a "click", but the firing pin won't actually be able to reach the primer, and the round will be completely untouched.

I've had issues with my own reloads before where either due to the brass not being sized properly, or the bullet being seated too far forward, it wouldn't go fully into battery. If you're not having any issues with factory ammo, I'd say this might be your problem, though I would think you'd definitely notice it being a lot harder to pull the bolt back and get the faulty round out of the chamber.

Yes, I really had to muscle the bolt back to get it to eject. I bought the brass from an midway USA and it appears to be within tolerances when I spot check them. Are you saying that the bullet isn't far enough into the case or it's to far? I'll try a few more and check.

 

[bobjones223]

Yes, I really had to muscle the bolt back to get it to eject. I bought the brass from an midway USA and it appears to be within tolerances when I spot check them. Are you saying that the bullet isn't far enough into the case or it's to far? I'll try a few more and check.

Sounds like maybe you are over flaring the brass, your projectiles are the wrong size, COL is to long, or your projectile profile doesn't work with your COL and throat location. Either way it is not going fully into battery and when it does go far enough to get ignition it is swelling into the chamber.

 

[DadSmith]

I've recently started reloading 300bo subsonic. I'm using 10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers. It seems that every once in awhile a round won't fire. I've only made a few at a time then test it out. I just had one not fire and manually ejected it, it didn't even look like the primer was hit. I put it back in and then it fired. I was just seeing if anyone had similar issues or advice on how to fix this. Thanks for any help.

Sheridan Engineering 300 BLK Slotted Ammunition Gauge

Sheridan Engineering 300 BLK Slotted Ammunition Gauge

ballistictools.com

Get you a cartridge gauge to check your reloads. These are basically used as a plunk test, but for rifle cartridges.

 

[AndreusMaximus]

Sounds like maybe you are over flaring the brass, your projectiles are the wrong size, COL is to long, or your projectile profile doesn't work with your COL and throat location. Either way it is not going fully into battery and when it does go far enough to get ignition it is swelling into the chamber.

Sheridan Engineering 300 BLK Slotted Ammunition Gauge

Sheridan Engineering 300 BLK Slotted Ammunition Gauge

ballistictools.com

Get you a cartridge gauge to check your reloads. These are basically used as a plunk test, but for rifle cartridges.

What they said.

 

[Paul 7.62]

If you are having chambering problems with a AR you have a potential of an out of battery firing. leading to bad JU-JU. So we have to find out why! First is a chamber gauge or checker, while ok doesn't mean you chamber is cut right but plan on it being ok. From the beginning size your case and check it in the chamber checker. If you get one from L.E.Wilson it has ridges on the top and bottom. this is to check if you case is too long or out of headspace. After sizing measure the case length to make sure your not too long and case is going into the bore of the gun. If all is well then move to case priming and powder fill. Seating the bullet check that you haven't bulged the case. run it through the case gauge. You should be good.

 

[BAgun]

If you are having chambering problems with a AR you have a potential of an out of battery firing. leading to bad JU-JU. So we have to find out why! First is a chamber gauge or checker, while ok doesn't mean you chamber is cut right but plan on it being ok. From the beginning size your case and check it in the chamber checker. If you get one from L.E.Wilson it has ridges on the top and bottom. this is to check if you case is too long or out of headspace. After sizing measure the case length to make sure your not too long and case is going into the bore of the gun. If all is well then move to case priming and powder fill. Seating the bullet check that you haven't bulged the case. run it through the case gauge. You should be good.

I ordered the case head/length gauge. Hopefully that will help solve the issues. I was using a micrometer to measure the OAL and keep it at the recommended length. But I wasn't having issues with factory ammo, so I'm assuming it's something I'm doing or not doing.

 

[STFU]

I've recently started reloading 300bo subsonic. I'm using 10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers. It seems that every once in awhile a round won't fire. I've only made a few at a time then test it out. I just had one not fire and manually ejected it, it didn't even look like the primer was hit. I put it back in and then it fired. I was just seeing if anyone had similar issues or advice on how to fix this. Thanks for any help.

I realize this is NOT the issue, but I am still stuck on this:
"10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers"

Is this a round you cooked these previously with success or is this a new round for you?
Almost all load data I see for the Hodgdon powders indicate you should be using SRM primers:


And yes, it does make a difference:

Magnum Primers vs Standard Primers

There are some significant differences in the magnum primers and standard primers for different guns. We're going to talk about what a primer is and why it's a necessary part of reloading. We'll also get into just what the biggest differences between standard primers and magnum primers are, and...

thecastlearms.com

My sub load have been very consistent since I started following the Hodgdon recipes exactly.
YMMV.

 

[bwframe]

What sizing die are you using? Seems as though I remember something about RCBS small based sizing dies solving some problems vs some others?

 

[BAgun]

I realize this is NOT the issue, but I am still stuck on this:
"10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers"

Is this a round you cooked these previously with success or is this a new round for you?
Almost all load data I see for the Hodgdon powders indicate you should be using SRM primers:
View attachment 268496

And yes, it does make a difference:

Magnum Primers vs Standard Primers

There are some significant differences in the magnum primers and standard primers for different guns. We're going to talk about what a primer is and why it's a necessary part of reloading. We'll also get into just what the biggest differences between standard primers and magnum primers are, and...

thecastlearms.com

My sub load have been very consistent since I started following the Hodgdon recipes exactly.
YMMV.

 

[BAgun]

I'm using a Lee loading dies and the package insert says to use 10.6gr of CFE BLK as a starting point for 220gr bullets. The brass I'm using is from Top Brass (ready to load bag). The primers I'm using are Remington 6 1/2 small rifle primers. I just got the head space gauge today so I'm going to check a few out tonight when I make up some rounds.

 

[edwea]

I realize this is NOT the issue, but I am still stuck on this:
"10.5gr CFE black powder, 220gr lead Hoosier bullets and 6.5 small rifle primers"

Is this a round you cooked these previously with success or is this a new round for you?
Almost all load data I see for the Hodgdon powders indicate you should be using SRM primers:
View attachment 268496

And yes, it does make a difference:

Magnum Primers vs Standard Primers

There are some significant differences in the magnum primers and standard primers for different guns. We're going to talk about what a primer is and why it's a necessary part of reloading. We'll also get into just what the biggest differences between standard primers and magnum primers are, and...

thecastlearms.com

My sub load have been very consistent since I started following the Hodgdon recipes exactly.
YMMV.

After reading this article, I still come away without a clear reason to use magnum primers in 300 blackout. The amount of powder (especially in subs) hardly requires a magnum primer. I understand that the load data calls for it, and that may be reason enough to use it I suppose.