Working with a new (to Me) rifle. Following the Optimal Charge Weight system found in the Reloading topics of the Articles. The cartridge is .358 Hawk, another variation of a 35 Whelen. At 97% max load I noticed some blow around the primer pocket. This is the first time I've seen this in my shooting experience, at least as I remember, most my experience was 40 years ago and the memory fades! I noted it in my 'over pressure' post shot case check, but thought it must be an aberrant case primer pocket flaw and continued on. The second 'Round Robin' shot at 100%, had a total blown out primer. I had to fetch it from the magazine after ejecting the shell. I stopped shooting the 100% and 101% loads after that. At home after check revealed that the first 100% shot showed some leakage around the primer that I hadn't noticed in the field, but the only 101% shot did not show any problems.

All these loads were with Qual-Cart cases and CCI primers. I checked some new cases and primers and they all are consistent with about 4 thousands interference fit. The one totally blown loose primer case head measurement was a few thousands over all the other fired cases. The gun is a Sako with custom barrel, basically a Mauser 98, three lug design.

Did some net reading and almost everybody says OVER PRESSURE!, with some excused recalled products. One source did make mention that high temperature shooting situations could cause unexpected / erratic high pressure situations, and this would apply to my situation, being in Texas in the high 90s F, and trying to rush the shooting session since the wife is waiting in the truck. NO, I'm not trying to blame it on her!

Regarding high temperatures, these loads were with H4895, which Hodgdon is marketing as one of their Extreme Rifle Powders. Those designed to produce consistent pressures / velocities across various temperatures.

Anyway, putting this out there for y'all to file away in your data banks and / or comment on. Analyzing the triangulated Points Of Impact from my session showed me to load about 97.5% of max. I'm gonna try it and see what happens from there. I hope to use this rifle this fall. Was very lucky in the New Mexico draws with Elk, Oryx (Gemsbok), and mule deer. Headed to Kentucky for the archery season and to harvest my grapes for wine this year. Will shoot the gun more there and see what happens, then going to NM for the hunts.

Sorry to be absent from the forums for several months. Like other members of the forum, we were dealing with the decline and now loss, of a four wheel drive furry family member and were totally committed to her final care. Thanks, doug

You should never have blackening around primers, let alone blown out. My first thoughts are that you are already over maximum FOR YOUR RIFLE. Chambers, seating depth and a multitude of other issues dictate that each rifle/cartridge/chamber determines its own maximum level. Add to the mix a wildcat that may or may not have chambering issues and the plot thickens.
It isn't the least bit unusual for the maximum load in one rifle to be less than that for another. I have several rifles that reach maximum one to two grains lower than listed data.
I would decide on the powder that best fits the cartridge pressure characteristics and start well below the listed maximum for your cartridge. Work up 3 cartridges for each load starting well under the listed maximum (as much as 10% is usually recommended) increasing powder charges by .5-1.0 grain increments until you see the first sign of pressure. Once that is reached STOP and back off to the last load that did not show pressure signs. That is the safe maximum pressure with that bullet, case. primer. seating depth and etc. for your rifle. From that point you can play with seating depth and etc. to tune that load for the best accuracy in your rifle. Changing any component will require you to start the entire project over.
Do not do your testing unless you have time to check each fired case thoroughly before firing the next. You may not reach what you think of as the velocity you want without changing powders, but you will need to start the process over if so. Blazing speed isn't worth much if the rifle is trashed in the process.
Best of luck to you and keep us posted on your results.

nothing I can add over what SSL has put other than to say,why bother with the extra velocity...back off to about your 95% load if it shows accuracy and be happy...the brass will last longer and so will you.

Thanks Guys, Your input made me pause and think. yeah, I'm being seduced by the Siren named Velocity. Gonna back down and start again. Appreciate the thoughts. Doug

Please don't take my post as criticism but concern for your safety. As you mentioned, velocity is a seductive pursuit, but often is an exercise in futility, if not danger. This can especially be the case with wildcats (or "semi-wildcats) with custom chambering that may or may not be of minimum dimensions in any given rifle. Lofty claims can be misleading and take a reloader down a treacherous path.
The rifles to which I referred all have snug chambers and reach nearly top velocities and best accuracy with less powder than listed as maximum. This is where a chronograph is essential. Velocity is a product of pressure. Once you reach a chronographed top velocity (assuming no pressure signs along the way), it is only logical to think that additional powder means excessive pressure.

Enjoy and please stay safe.

The guys have pretty much summed it up Like.358s. Only things I would add is give some consideration to a slower powder and start your load development from scratch, and measure your chamber throat...maybe make a cast...in case you are seating your projectiles right into the rifling, which can lead to higher pressures.

I’m not familiar with that brand of case, but if their website blurb is to be believed, they are a premium case, so you shouldn’t have problems from that area.

SingleShotLover wrote:

Please don't take my post as criticism but concern for your safety. As you mentioned, velocity is a seductive pursuit, but often is an exercise in futility, if not danger. This can especially be the case with wildcats (or "semi-wildcats) with custom chambering that may or may not be of minimum dimensions in any given rifle. Lofty claims can be misleading and take a reloader down a treacherous path. The rifles to which I referred all have snug chambers and reach nearly top velocities and best accuracy with less powder than listed as maximum. This is where a chronograph is essential. Velocity is a product of pressure. Once you reach a chronographed top velocity (assuming no pressure signs along the way), it is only logical to think that additional powder means excessive pressure. Enjoy and please stay safe.

That's one of the things I was noticing in my re-think. With 1% increases in powder here's a list of the velocity increases (fps).
A to B +92
B to C +60
C to D +19
D to E +39 (E was first partial blow by primer)
E to F +22
F to G +23
G to H -2 (H was thought to be 100% & was total blown primer)
H to I -2

So it's diminishing returns after C. That's gonna be my new 100%, boosted from it's previous position of 94%.

Thanks for helping, good thoughts. doug

Vince wrote:

The guys have pretty much summed it up Like.358s. Only things I would add is give some consideration to a slower powder and start your load development from scratch, and measure your chamber throat...maybe make a cast...in case you are seating your projectiles right into the rifling, which can lead to higher pressures. I’m not familiar with that brand of case, but if their website blurb is to be believed, they are a premium case, so you shouldn’t have problems from that area.

Thanks Vince, I'm pretty far off the lands so I don't think that was an issue. Am thinking a slower powder would be good. Varget is reported as good. By backing down the charge I'm leaving some unfilled room in the case. A slower powder might fill it better, but I'm not sure how much empty space becomes an accuracy issue in rifle cases? I've read it's more of a concern in pistol cases? My new 'max' load will fill the case 95% volume.

Thanks, doug

Lljke.358s,
Those cases with the ring od carbon around the peimer my now have primer pockets that are too large to seal a primer so you should mark then to see if you get leakage with your safe loads.
You probably all ready knew that but I said it and maybe a newb will get the message.