[longbow]

OK longtime reloading gurus, I need somebody to stand back and take a look and see what I'm missing here. I'm no stranger to high-pressure reloading and I know I'm doing it and what's causing it when it happens. I run hot loads on purpose in some guns. This one, however, has me stumped.
I just finished building a 300WSM and high pressure signs are killing me. This is a build I did myself. It's a Remington 700 SA platform, PTG short action bolt with a mag boltface (.550), X-Mark Pro trigger set at 1.75, a 1-10 5R barrel and a Stocky's Classic stock. I was VERY careful with the chamber and it came out nice and smooth. I haven't polished it yet and won't need to.
I've tried roasting RL17, H414, W760 and H380. I've tried loads below minimum with all powders and still got hard boltlift, flattened primers and shiny half-moons from the extractor. With all loads, 90% of the time the spent cases stick in the boltface and won't eject. Boltface ID is .550 and my fire brass casehead is .553 - .555. :shock: Persian Blue shows I have nearly full contact on both bolt lugs. I didn't true up the lugs because they ended up being near-perfect allready. All I did was lap them a bit.
My headspace to my PTG go-guage is .002. The gap from bolt shoulder to barrel seat is .017. Brass neck thickness is .015 for new and third-fired brass. Reloaded brass necks measures .337. Fired brass is .344. Clearly, at .007 there's plenty of neck clearance.
I'm running Federal brass, Federal Mag primers and 168gr A-Max bullets. The jump to my lands is .780. I haven't tried adjusting my OAL yet.
What else do I need to look at? What am I missing?

 

[Springville Shooter]

This one has me stumped. Only thing I can think of is a defect in the actual rifling. Have you mic'd out a fired case to verify that there are absolutely no abnormalities in the chamber. Have you inspected the camber/throat with a bore scope? Other than these few long shots, I'm clueless.-------SS

 

[Springville Shooter]

You should pose this question on The long Range Hunting site. There are a dozen or so rifle builders on that site who have a lot of experience.-----SS

 

[longbow]

Here's my test loads:

RL17 - 65.0, 65.5, 66.0
Relliant recommends 68.0grs

H414 - 60.0, 60.5, 61.0, 61.5, 62.0, 62.5, 63.0, 63.5, 64.0, 64.5, 65.0
Hodgden recommends 61.0 - 65.0

W760 - 60.0, 60.5 (I quit after those two)
Hodgden recommends 61.0 - 65.0

My finished gun:

 

[longbow]

This one has me stumped. Only thing I can think of is a defect in the actual rifling. Have you mic'd out a fired case to verify that there are absolutely no abnormalities in the chamber. Have you inspected the camber/throat with a bore scope? Other than these few long shots, I'm clueless.-------SS

I mic'd my fired cases and there's nothing out of spec except the casehead expansion.
I don't have a bore scope here so I can't look at my bore.

 

[Loke]

the powders seem to me to be on the fast side for a magnum case. How are your velocities? Are they in line with what you are expecting? Too fast? Too slow? Just throwing out ideas, because I don't really know...

 

[longbow]

You should pose this question on The long Range Hunting site. There are a dozen or so rifle builders on that site who have a lot of experience.-----SS

I did that. It's in the reloading section by LRSickle. I tried calling Chad Dixon from LongRifles.com. He's helped me out on quite a few things. JE Customs did some work on a Mark V for me. I'm hoping he'll chime in as well as my good friends Franklin and Broz.

 

[longbow]

the powders seem to me to be on the fast side for a magnum case. How are your velocities? Are they in line with what you are expecting? Too fast? Too slow? Just throwing out ideas, because I don't really know...

My cronys are in storage down in Perry. I have a MagnetoSpeed coming soon (Monday?). It's been on backorder for months and I've been dying to crono these loads. I'll let you know what I find out.

I have a friend who went to Los Anchorage for the weekend with a blank check of mine and is looking for a keg (or even a pound) of IMR4350.

 

[Critter]

I haven't seen it mentioned but have you tried a factory round?

 

[Springville Shooter]

I think JE nailed the problem on the other forum. Let us know how it turns out.-------SS

 

[longbow]

I haven't seen it mentioned but have you tried a factory round?

No I haven't but I have a friend coming back from Los Anchorage on Monday and that was one of the things on my shopping list I sent with him.

 

[longbow]

I think JE nailed the problem on the other forum. Let us know how it turns out.-------SS

I will. JE is a Mark V action guru and he knows his stuff about most other actions as well. I'm way overloaded today with maintenance stuff so I won't be able to get to it until later tonight. Can't wait.

 

[longbow]

Well JE Customs on another forum figured it out. It's not the first time he's helped me.
The cases on a 300WSM have rebated rims. The new bolt wouldn't let the shoulder seat properly and when fired, the cases slammed back into the bolthead causing a slapstick effect and expanded just enough to wedge itself in my bolt face. Since this is my first short mag I've built, I didn't take the bolt rim into account.
For right now, I live on an island in the Gulf of Alaska and things are hard to come by. We have a lathe in my shop, (compliments of the Alaska Game and Fish), that has been sitting idol under a black cover for years. One other maintenance guy and I are the only ones who have used it for years. I had to make a bolt holder out of aluminum block to hold my bolt in the four-jaw chuck. It burned up most of my weekend but I got it done and my bolt functions great now. Now back to load development.

Thanks to all that replied!!

 

[swbuckmaster]

Cool you can work on your own stuff like that