Too much jump/pressure 300 WSM

[Crgchck]

I’m not a reloading expert and only load for accuracy don’t give (2) shits about speed.
I load to the length my rifle likes and then learn dope of the load by shooting.
I do use a book/net for charge parameter..
I’ve been recently questioned on a rifle of mine. Logic vs what the rifle is telling me, makes me question an issue I have.
.300 WSM factory ammo showing signs of pressure. All factory ammo.
Starting my elementary reloading process, I see that my round is unusually long. Again I don’t really care about specs nor sammi.. so I run that length and play with charge… starting in the middle of charge parameters and reaching max.. find where I want to be.. and load away..
Heres what logic makes weird.
Factory ammo is a MFR to extract. The primers of some have fallen out; most are flat and I’m actually getting a pimple on the brass from ejector pin hole.
Hand loads: Loading to just shy of lands and with pretty heavy charge, I’m not seeing any pressure signs.
The only problem with that is the only rounds I can load with suitable accuracy that will go into any short action mag box is the lapua mega.
In my small brain, it seems jamming to the lands or being closer would cause more pressure than having a lot of jump..
if it were a hand load with a heavy charge and the bullet was eating case capacity I could see it but we are talking factory loads..
What am I missing?
This is more of a curiosity as I’ve settled on using the Mega’s as hunting rounds and utilize the rifle as a single shot while loading longer bullets for shooting paper.

 

[Crgchck]

Nothing?

 

[FredHammer]

Sounds like you have a short throat and the Mega works because you are able to seat it further out as the bearing surface contact point of the bullet is further towards the tip of the bullet. Contrasted to a long pointy ELDM or such VLD bullet where the bearing surface contact is further towards the base of the bullet and the long pointy portion of the bullet eats up space in the mag.

Pressure is on a slide rule/continuum. You can start to pressure seated too deep and eating case capacity, or you can seat too long with a jam + seating.

I suggest you determine if the factory ammo is jammed in the rifling too much and thus causing the over pressure condition. I know you said you don't care about specs, but this is a spec you should really care about for this reason. You did say that you are loading "near the lands" so apply this method of determining DTL to all rounds.

 

[Crgchck]

Sounds like you have a short throat and the Mega works because you are able to seat it further out as the bearing surface contact point of the bullet is further towards the tip of the bullet. Contrasted to a long pointy ELDM or such VLD bullet where the bearing surface contact is further towards the base of the bullet and the long pointy portion of the bullet eats up space in the mag.

Pressure is on a slide rule/continuum. You can start to pressure seated too deep and eating case capacity, or you can seat too long with a jam + seating.

I suggest you determine if the factory ammo is jammed in the rifling too much and thus causing the over pressure condition. I know you said you don't care about specs, but this is a spec you should really care about for this reason. You did say that you are loading "near the lands" so apply this method of determining DTL to all rounds.

I don’t want to be that guy that asks for info then debates offered info but it seems the opposite.. any other bullet seated is so long that it won’t go in mag.. the mega is right at max mag length. So it’s not that I’m having to load short.. I’m having to load long but it doesn’t make sense that shorter factory ammo is showing signs of high pressure.

 

[FredHammer]

If the factory ammo is not jammed in the lands to create the over pressure condition, then something is up with the powder and/or charge weight. You could have a smaller than spec chamber. Hard to know without the components and rifle in hand. All I can try to do is spark an idea or new tests to help you fix your issue.

The easy button for a mag restricted rifle is to load .010 off the front of the mag for reliability of feeding and then adjust powders and charges to make the groups small without over pressure.

 

[Aftermath]

You are very correct in thinking that pressure is higher closer to and jamming than with jump....until that bullet is seated VERY deep.
I would be using instruments to determine exactly where the lands are and exactly how long the CBTO is on each bullet. If you do not have measuring tools, you can also remove the ejector and use the free falling bolt handle method to find the correct shoulder bump and the CBTO for your combination of stuff.

LOTS of info in these threads:
https://www.snipershide.com/shootin...-doing-actual-node-or-just-pass-fail.7156697/

Seating Depth is this too much?

I’m new to reloading any advice would help. 6.5 Creedmoor 140g Nosler, using H4350 up to 40.8g. Am I just asking for pressure issues seating the bullet this deep?

www.snipershide.com

 

[Emerson0311]

I’m not a reloading expert and only load for accuracy don’t give (2) shits about speed.
I load to the length my rifle likes and then learn dope of the load by shooting.
I do use a book/net for charge parameter..
I’ve been recently questioned on a rifle of mine. Logic vs what the rifle is telling me, makes me question an issue I have.
.300 WSM factory ammo showing signs of pressure. All factory ammo.
Starting my elementary reloading process, I see that my round is unusually long. Again I don’t really care about specs nor sammi.. so I run that length and play with charge… starting in the middle of charge parameters and reaching max.. find where I want to be.. and load away..
Heres what logic makes weird.
Factory ammo is a MFR to extract. The primers of some have fallen out; most are flat and I’m actually getting a pimple on the brass from ejector pin hole.
Hand loads: Loading to just shy of lands and with pretty heavy charge, I’m not seeing any pressure signs.
The only problem with that is the only rounds I can load with suitable accuracy that will go into any short action mag box is the lapua mega.
In my small brain, it seems jamming to the lands or being closer would cause more pressure than having a lot of jump..
if it were a hand load with a heavy charge and the bullet was eating case capacity I could see it but we are talking factory loads..
What am I missing?
This is more of a curiosity as I’ve settled on using the Mega’s as hunting rounds and utilize the rifle as a single shot while loading longer bullets for shooting paper.

What rifle, barrel, chamber etc? All factory, sammi chamber and barrel, or something you or a gunsmith put together? What bullets are you reloading with and what bullets is the factory ammo using? If it’s a factory rifle, not your screwup. If not, it’s you or the person who put it together.