Need help: what's causing this!?

[jonthomps]

I've never seen this powder burn pattern before. I've always seen burn residue on the neck, but never going down the shoulder. This is the first reload on Norma brass. Caliber is a 300NM. Powder is H1000. Charge weight is 86.5grs under a Berger 215gr hybrid. I am using Forrester die set: FL resizer and micrometer bullet seater. Both pictures are of the same two rounds - just different sides. What am I doing wrong and how do I correct it? Thanks.

 

[Kristian72]

How much case lube did you use?

 

[MagnumManiac]

I've never seen this powder burn pattern before. I've always seen burn residue on the neck, but never going down the shoulder. This is the first reload on Norma brass. Caliber is a 300NM. Powder is H1000. Charge weight is 86.5grs under a Berger 215gr hybrid. I am using Forrester die set: FL resizer and micrometer bullet seater. Both pictures are of the same two rounds - just different sides. What am I doing wrong and how do I correct it? Thanks.

How much below the suggested maximum charge is your load?
Normally, you only see this with low pressure or a charge that is igniting errattically causing an improper burn.
I have no experience with the Norma Mags, what is the case capacity in grains of water?
May be you need a slower powder, or a double base powder of similar burn rate, like RE25 or RE22.

Not sure what's causing your problem, maybe a low powder charge.

Cheers.
gun)

 

[jonthomps]

How much case lube did you use?

Used RCBS case lube when resizing. I'm thinking it may be a low charge issue, but what's your line of thinking behind the cases being lubed?

 

[jonthomps]

How much below the suggested maximum charge is your load?
Normally, you only see this with low pressure or a charge that is igniting errattically causing an improper burn.
I have no experience with the Norma Mags, what is the case capacity in grains of water?
May be you need a slower powder, or a double base powder of similar burn rate, like RE25 or RE22.

Not sure what's causing your problem, maybe a low powder charge.

Cheers.
gun)

I shot 89grs of H1000 and it was too hot - stiff bolt lift and ejector marks. I backed it off to 86.5 and this is what I got. I'm betting you're right, I need to up the charge weight a smidge. I loaded 20 at 87.5. We'll see what happens at that load weight. Double base powder is a good idea too.

 

[Corey Schwanz]

Looks like the case neck isn't fully expanding to seal the chamber when it fires, potentially too weak of a load. If your brass had a few firings on it, I'd say it might be work hardened a tad and in need of some annealing but with new brass, that shouldn't be the issue. We list the loads for that cartridge/bullet combo as 83.5 minimum and 87.7 maximum with an OAL set at 3.680. Loads can change with seating depths. A slower powder like Retumbo or N570 might work too.

 

[Outlaw6.0]

I shot 89grs of H1000 and it was too hot - stiff bolt lift and ejector marks. I backed it off to 86.5 and this is what I got. I'm betting you're right, I need to up the charge weight a smidge. I loaded 20 at 87.5. We'll see what happens at that load weight. Double base powder is a good idea too.

Did the case exhibit the same characteristics at the 89grn charge weight?



t

 

[idaho elk hunter]

I have had the same results on a second load with Norma Brass. Over max loads!

 

[Bill Johnson]

The simple answer is that the neck is not sealing prior to being exposed to burning powder. H1000 is hard to ignite so use a good magnum primer like Fed 215 and be sure you have good neck tension, .003 minimum, .005 better and/or possibly even a crimp like the Lee factory crimp. What sometimes happens is that a high energy primer will, by itself, start the bullet moving before good powder ignition. The result is low pressure initially, leading to smoked shoulders.

 

[jonthomps]

^^^^ Interesting. That makes sense. Much appreciated.

 

[barefooter56]

jonthomps,
Try working up in 1/10th grain increments from the 86.5 grain load instead of the 1 grain jump. The guys are right in that the case neck isn't being blown out quickly enough to seal in the chamber. Unless the soot is going down onto the case shoulder/body itself it may not be as bad as you think. Check your accuracy as you increase the load checking for pressure. IF you find an accurate load and there is still soot on the neck just below where there is less or no soot on the neck but the accuracy is degrading . You may have to put up with it and just clean your cases longer. Just adding to the already great suggestions above. FYI