High pressures at minumum loads and under.

[LRSickle]

I just finished building a 300WSM and high pressure signs are killing me. I've tried roasting RL17, H414, W760 and H380. I've even tried loads below minimum with all powders and still got hard boltlift, flattened primers and shiny half-moons from the extractor. When I pull my PTG bolt back the spent case sticks in the bolthead and won't eject. Boltface ID is .550 and my fire brass casehead is +/- .555.
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 neck measures .337. Fired brass is .344. Clearly 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.
I'm an accomplished reloader and I can't figure this out. What else do I need to look at? What am I missing?

 

[just country]

morning, what is the charge weights of the different powders. as u know the WSM

cases hold a substantial amount of powder. the powders u listed r fast on the burn

rate. I have a 7WSM I shoot 66.5grs, 4831sc. with a Barnes 145grs mrx. the build

721 rem. la action sako extractor, opened bolt face, 29" #4 shaw barrel, vais

vais muzzle brake. A4 stock. worked hard to find magic number.

u could try a slower burning powder. Ramshot Magnum is one of my favorite

for the magnum cases. All the powders u listed I use in my 22-250-243-308,

smaller cases. In my 300win. I use MRP or the old 4831. 78.5 grs. up to

180grs bullets. over 180's I back off to 78.0grs.

sounds like the wrong powder?

food for thought

Just Countrylightbulb

Life Member NRA
Life Member TSRA

 

[prm]

hey
what weights did you load with rl 17


I load norma urp in my 300 wsm
it is close in burn rate with rl17
Winchester brass
federal 215 lrm match
barnes 168 grains
63,5 grains urp
no pressure signs

 

[LRSickle]

sounds like the wrong powder?

food for thought

Just Countrylightbulb

Life Member NRA
Life Member TSRA

That may be. I'm going with Hodgden and Relliant recommendations with the available powders I have on hand. My biggest problem is I live on an island in the Gulf of Alaska and I can't buy powder over the internet unless I have it shipped to PAF in Seattle and put on a barge for Kodiak. Then I have to figure out a way to get a bush pilot or friend to pick it up and bring it here the next time he comes. It's a logistical nightmare. Anyway, here's my 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

 

[LONGSHOOTER]

Have you verified that your scale is accurate?

 

[J E Custom]

One of the problems I have seen with the WSMs is that the bolt face rim needs to be chamfered
to clear the case body. The rem on WSM cases are smaller than the case body. (The WSMs are a rebated rim case)if this is not done it changes the head space and upon firing drives the case back until it contacts the bolt face.

To check if this is the condition, take a small ball of Play dough (about 1/16''),place it on the bolt face and insert a sized case in the bolt and see if there if any flattening. also If the bevel is not there
the case will rock back and forth like it is a ball socket.

Just something to look for

J E CUSTOM

 

[LRSickle]

Have you verified that your scale is accurate?

Yes. It's right on.

 

[LRSickle]

One of the problems I have seen with the WSMs is that the bolt face rim needs to be chamfered
to clear the case body. The rem on WSM cases are smaller than the case body. (The WSMs are a rebated rim case)if this is not done it changes the head space and upon firing drives the case back until it contacts the bolt face.

To check if this is the condition, take a small ball of Play dough (about 1/16''),place it on the bolt face and insert a sized case in the bolt and see if there if any flattening. also If the bevel is not there
the case will rock back and forth like it is a ball socket.

Just something to look for

J E CUSTOM

That's the best lead I've heard so far. I have some clay left over from the bedding job so I'll try that.
If I need to chamfer the rim, what degree/bevel do I need? I'm guessing my headspace isn't wrong because my go-guage sets back nicely against my bolt face. Right?

 

[Laelkhunter]

What about trimming the case OAL to "trim to" length, or did I miss that you already did that (sorry if I missed it).

 

[LONGSHOOTER]

http://www.saami.org/PubResources/CC_Drawings/Rifle/300 Winchester Short Magnum.pdf

 

[Ridgerunner665]

Oil/lube left in the chamber can cause this... Also sizing lube left on cases.

It can vary from ejector marks all the way up to blown primers...

Make sure the chamber is mopped out and completely dry after cleaning and I drop my brass in a bowl of acetone to remove the sizing lube.

 

[LRSickle]

What about trimming the case OAL to "trim to" length, or did I miss that you already did that (sorry if I missed it).

I didn't post it but it is one of the things I looked at. I trimmed my cases to 2.098.
Good reply though Laelkhunter. Thank you.

 

[LRSickle]

Oil/lube left in the chamber can cause this... Also sizing lube left on cases.

It can vary from ejector marks all the way up to blown primers...

Make sure the chamber is mopped out and completely dry after cleaning and I drop my brass in a bowl of acetone to remove the sizing lube.

This is something I've heard causes problems but I've never seen it. I did mop my chamber out and cleaned my brass with alcohol on my second time out and it didn't seem to make any difference that I could tell. Good thought though Ridgerunner665, you never know what little thing can cause havoc.

 

[Ridgerunner665]

I've seen it...several times...sorry it wasn't your problem.