300 WSM pressure issues?

[Woodworker74]

Last night I was sighting in a newly mounted scope on the rifle I recently purchased- a Tikka T3 Hunter in 300 WSM. I love this rifle. If I could just learn to shoot, it's accuracy would be amazing. Anyway, I sighted in using Winchester 150 gr SuperX factory ammo. Upon shooting a few more than it should have taken, I switched to hand loads, utilizing a variety of bullets, powders and once fired brass. After shooting a number of different combinations, there were a few clear favorites (see target photos). The 185 gr Berger Hybrid hunting bullet over W760 powder being the best. Anyway, after a good amount of shooting, I started to notice that a few loads were causing a stickier bolt than others. And then.... a primer blew completely out, spewing hot gas and a tiny little piece of metal into my face.

Now, let me just state a couple things for the record.
#1- NONE of these loads were over published max. All were between 1.5 and 2 grains below max.
#2- I'll admit publicly that I did NOT work these up a few grains at a time. I was simply looking for a good hunting load for bear. Something that had some punch to it. Soooo, I started at a grain or 2 below max, and I accept responsibility for my stupidity.

That being said- do BOTH of the photos seem to show signs of high pressure? The shell in my hand is a factory round that definitely has a mark that I'm guessing is an extractor mark, and the primer looks a bit flat and slightly cratered to my eye too. The hand loads (yes, that's nail polish- it helps me keep my loads straight) seem to show the same thing and possibly some cratered primers?? I guess what I'm driving at is this- the WSM is a high pressure cartridge to begin with. If I'm seeing signs of that with factory ammo AND hand loads, should I be as worried as I am? Was the blown primer a fluke? I've read so much conflicting info on how accurate a gauge of pressure things like primers, shine marks etc. really are. Opinions please!!! Oh, and if anyone has some shooting pointers to help me tighten up these groups- please offer them up too! Thanks!

 

[243winxb]

a stickier bolt

utilizing a variety of bullets, powders

Different Component = Different Pressure. The 300 WSM at 65,000 PSI is about all brass can handle. The missing primer is the only high pressure i see.

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[jmr40]

Buy a chronograph!!!

The problem with using conventional pressure signs is that they don't show up until around 70,000 psi. The best way to know is with a chronograph. If the loads are faster than expected they are overpressure. All but the one without the primer look OK to me, but that doesn't prove anything either way. You may want to consider OAL, they may need to be seated a bit deeper for that rifle. If your bullets are jammed into the lands it can lead to excessive pressure.

I've never used that powder. From my online research the 2 that I see recommended most often are H4350 and RL17. I've tried both. I got almost 100 fps more speed with RL17, but also started getting over pressure signs, (confirmed by excessive speeds on the chronograph) at 2 gr below book max.

Most people are getting a little less speed, but better accuracy with H4350. That was my experience too. A max load was shooting 180's at 2950 fps with excellent accuracy and no pressure signs. Very tolerable recoil and right on what the books say it should be. But others are getting the extra speed from RL17 and claim no problems. It really depends on the rifle.

I reached just under 3050 with the RL17 before I hit the max listed in the books. Accuracy wasn't as good and I just never felt comfortable with the load.

 

[Casefull]

I am having good results with superformance powder. 3190 fps, 1 grain under max with 180 ttsx. I was getting ok results with rl17 at 3000 fps. Odd thing with the superformance the groups tightened to under an inch and the rifle shoots softer than the slower rl17. Rifle is kimber Montana.

 

[Archie]

Overpressure? Perhaps.

The factory round with the Winchester head stamp looks okay to me. Yeah, maybe there's an extractor mark.

Note the fired round in the last photo in the upper left hand corner. It has what appears to be 'smudging' from powder gas leakage around the primer. That is a sign of overpressure. (Gas escaping around the primer. Too much pressure or really beat up primer pockets.) The missing primer is another gentle reminder of too much powder.

I note both cases that I think are high pressure are both R-P marked. I'm suspecting the R-P cases may be heavier - and therefore smaller in internal volume - than the Winchester cases. (Or the Norma, for that matter.)

I'll echo JMR40's suggestion. Buy a chronograph. Watch the velocities and see if they're about what you expect or much higher (or lower). As you already know, start from the bottom and work up. I'll also suggest using all new and as uniform as you can get it, brass for testing purposes. In a high pressure round like that, they may not last all that long anyway.

Good luck and be careful.

 

[gamestalker]

I don't see any obvious high pressure signs on the case head or primer flow. In fact, I see very minimal primer flow. And although primers aren't always the best way to read pressures, doing so can help when combined with all other indicators, but only if your familiar with the primer being used, and the visible characteristics of primer flow .

Bolt lift, primer flow, extractor transfer marks, and chrony results are good when used together.

As far as transfer marks, I've seen some pretty defined transfer marks with R.P. brass when all other head stamps had none. And that has been with below starting table loads with RP, in which other head stamps had been worked up to near max and showed nothing. So I've since realized and experienced that RP brass is much softer than Win and several others.

Search the data for slower burning powders also. Higher velocities are easier to obtain with slower burning powders, as faster burners can often spikey up around the top end.

RL19 and RL22 should be more pressure compatible with working up toward the top end for 300 WSM. Also, Hybrid100V, Supreme780, and even IMR-7828 operate at lower pressures while delivering upper end velocities.

And a major factor that can drive pressure up even when your not on the bleeding edge, is oal. If the bullet is close, or into the lands, pressures can go sky high. Anything closer than .010" off the lands is usually going to show increased pressures. And different bullets engrave differently, this too can cause pressure increases when getting up close to the lands. I have many years experience seating into the lands, it's a tricky process.

But I'm not suggesting that your using a wrong powder, W760 should be very manageable if worked up properly, something I believe you stated you did not do.

I think a good safe approach to your issue would be to use a chrony to help determine how high your pressures are running. And do a proper load development, start at a reasonably low table charge and work up in reasonable increments. That doesn't necessarily mean start at the absolute minimum charge, but maybe some where around 25% of the table, then working up in 10% or 15% table increments until you get to about 80% of the table. If at 80% table your not satisfied, then maybe continue in 5% table increments, this will help prevent bad things from happening.

GS

 

[steve4102]

#1- NONE of these loads were over published max. All were between 1.5 and 2 grains below max.

Not according to Hodgdon.

Both of your loads are 1/2 (.5) gr below max.

http://www.hodgdonreloading.com/data/rifle

 

[ironworkerwill]

243winxb nails this one. They are factory loaded as hot as possible and any increase over the factory loading will be over pressure. This is true with all the short mags and super short mags.

The faint circle on the head of the case with missing primer shows head extrusion into the ejector hole. Stick a fork in it, it's done.

H414(w760) is a good all around powder for 300wsm IMO. It meters great and is accurate.
Hyb 100V does show lower pressures with competitive velocity, it may be something to look into.

Gamesalker brings up a valid point on OAL. Pressure can be a bugger if your at max pressure and are too close to the lands. A good full pressure load at min COL can be WAY over pressure if you are touching the lands.

 

[Woodworker74]

"Not according to Hodgdon.

Both of your loads are 1/2 (.5) gr below max."
- Steve4102, Nosler data says 2 gr below max on the Bal Tip. But yes, you're right on the other one. I miss spoke, the Berger load is .5 below max based off Hogdon data for a 190 gr Sierra HPBT.

"Note the fired round in the last photo in the upper left hand corner. It has what appears to be 'smudging' from powder gas leakage around the primer. "
- Archie, I was afraid that might be interpreted that way. It's black nail polish. I color code my different loads so I can look back to cross-reference the brass with the load data.

In reference to what everyone else was saying. I DO have a chronograph. I didn't use it this time, and it bit me. I use an overall length gauge to set my loads back the desired distance from the lands. But perhaps some of them were too close. That is something I need to read more on- as far as how close or far off lands to seat different bullets. I also use a Wilson case gauge to check for case length and tolerances. With all that being said, this should be a good lesson for not just myself, but other new reloaders to TAKE YOUR TIME to work up a load. And to utilize all the tools at your disposal. I have been reloading without incident for about 3 years now, but I didn't do those things, and I should have. Bottom line is I rushed to get a load that packs a wallop, and I ended up being the one getting walloped. Thanks guys for all the opinions and advice. All very helpful as usual.

 

[hoghunting]

I don't see any obvious high pressure signs on the case head or primer flow.

I don't see a problem with them either. Are you loading your rifle from the magazine or placing each round in by hand? If your loads fit in your T3 magazine, it's very doubtful that the bullet is touching the rifling.

 

[Grumulkin]

That being said- do BOTH of the photos seem to show signs of high pressure? The shell in my hand is a factory round that definitely has a mark that I'm guessing is an extractor mark, and the primer looks a bit flat and slightly cratered to my eye too. The hand loads (yes, that's nail polish- it helps me keep my loads straight) seem to show the same thing and possibly some cratered primers?? I guess what I'm driving at is this- the WSM is a high pressure cartridge to begin with. If I'm seeing signs of that with factory ammo AND hand loads, should I be as worried as I am? Was the blown primer a fluke? I've read so much conflicting info on how accurate a gauge of pressure things like primers, shine marks etc. really are. Opinions please!!! Oh, and if anyone has some shooting pointers to help me tighten up these groups- please offer them up too! Thanks!

1. I wouldn't call any of the photos except the one with the blown primer indicative of high pressure. Were you weighing charges or throwing them? Is it possible you got a little more powder than you should have by accident?

2. You can use a Sharpie to color primers which is probably faster and less messy than using nail polish.

3. It's best to have a number load data sources. I have ones by Hornady, Speer, Barnes, Nosler, Lee and Hodgdon. There are cases where the starting load in one manual is higher than the maximum load in another manual. It's best to start load workup conservatively. Remember that in your load workup something will ALWAYS be different than what was used for the data in the manual be it a different primer, case, rifle, etc.

4. Do ya'll know that as pressure increases to dangerous levels velocity many times decreases? It is erroneous to depend on a chronograph to tell you if pressure is OK. On one forum a test was discussed in which a purveyor of firearms and a hand loader tested velocities in 10 different supposedly "identical" rifles. Velocities with "identical" loads varied as much as 200 fps. Velocity is an indirect sign of pressure and I don't use it at all in load workup.

5. I know that there has been hooting and hollering about how pressure signs on primers isn't dependable. Sorry. While you can't take the look of a primer touch off in one gun and necessarily expect the same thing to happen in another, in a lot of rifles it is a good means of comparing pressure. In shotgun and some handgun loads where pressure needs to be lower it is pretty worthless to look at primers however.

6. Conventional pressure signs show up well below 70,000 psi.

 

[Woodworker74]

I am loading for the factory mag. As long as possible where desired, but still just fitting the mag.

 

[gamestalker]

Though I employ a combination of methods to read pressures, I have used primer flow as a reliable means to identify pressures. And when I feel increased bolt resistance, primer flow, and bolt / case head transfer, have always been quite reliable for me. But I have used the same primer brand for better than 30 yrs..

Using the chrony however can be tricky at best. I have multiple rifles of the same caliber, and each has a different barrel speed, some by a significant degree. So unless I've established that barrels speed, along with a particular powder and bullet, it provides very little insight.

So what works best for me, is bolt lift, case head / bolt transfer, and primer flow. Used together, I have been quite successful in monitoring pressures.

And I don't rely on primer flow for AL pistol loads, it's very difficult to read primers under such circumstances, IMO. Although I do for revolvers.

GS

 

[Woodworker74]

1. I wouldn't call any of the photos except the one with the blown primer indicative of high pressure. Were you weighing charges or throwing them? Is it possible you got a little more powder than you should have by accident?

2. You can use a Sharpie to color primers which is probably faster and less messy than using nail polish.

3. It's best to have a number load data sources. I have ones by Hornady, Speer, Barnes, Nosler, Lee and Hodgdon. There are cases where the starting load in one manual is higher than the maximum load in another manual. It's best to start load workup conservatively. Remember that in your load workup something will ALWAYS be different than what was used for the data in the manual be it a different primer, case, rifle, etc.

4. Do ya'll know that as pressure increases to dangerous levels velocity many times decreases? It is erroneous to depend on a chronograph to tell you if pressure is OK. On one forum a test was discussed in which a purveyor of firearms and a hand loader tested velocities in 10 different supposedly "identical" rifles. Velocities with "identical" loads varied as much as 200 fps. Velocity is an indirect sign of pressure and I don't use it at all in load workup.

5. I know that there has been hooting and hollering about how pressure signs on primers isn't dependable. Sorry. While you can't take the look of a primer touch off in one gun and necessarily expect the same thing to happen in another, in a lot of rifles it is a good means of comparing pressure. In shotgun and some handgun loads where pressure needs to be lower it is pretty worthless to look at primers however.

6. Conventional pressure signs show up well below 70,000 psi.

1. Weighing all charges. It is possible that the charge was too heavy. I had been having some issues with my Lyman electronic scale, though I thought they were sorted after calling and getting some directions from their tech support.

2. I know I could, but I like the pretty colors.

3. I was using Hornady manual, Hogdon's new manual, Nosler info, Barnes manual and Lyman manual.

4. I don't worry too much about velocity to start with. I'm more worried about accuracy. In this case, I was trying for more umph, but took an admittedly stupid shortcut. (shooting a 300 lb bear through both lungs at 40 yards and then having it charge you leaves you with the desire for a little more wallop). I'll usually check for velocity AFTER I've got an accurate load. An animal won't notice a 2-300 FPS difference until it's further out than I care to shoot.

Thank you all for the input. Gamestalker as well. Like I said before, I've been re loading for only about 3 years now and I know I have so much more left to learn. That's what I love about it though, there's always something else to learn.

Oh, and Ironworker- I do have some 100V that I used in this work up as well. I got fairly good accuracy (and no pressure signs) with it combined with 165 gr GMX bullets. I think that may be the load I go with for bear this weekend.

 

[Grumulkin]

Weighing all charges. It is possible that the charge was too heavy. I had been having some issues with my Lyman electronic scale, though I thought they were sorted after calling and getting some directions from their tech support.

I've always used a balance beam scale and I have the standard weights to check it with. Though an electronic scale would be convinient, I've never trusted them; the more high tech the more to go wrong you know.

 

[gamestalker]

Ya, me too, I tried an electronic, but it was finicky and unreliable. So I've written them off, my little RCBS 5-10 is all I trust any more.

Glad you got things figured out, enjoy that T3.

GS

 

[GooseGestapo]

Don't mix different head stamp brass!
From personal experience, Norma has the greatest capacity, Remington the least, except for maybe Federal.
I don't have any experience with the .300wsm, but do with a .257wby. Good safe loads in Norma brass (makes Weatherby ammo/brass) will lock up the action and blow primers with Federal factory brass, or reformed R-P 7mmRemMag brass.
Seems you mix- matched components with a high end performance cartridge.
Always back off 10% unless using EXACTLY the same recipe. Even then it's still a good practice.

 

[ironworkerwill]

I doubt he had a problem with w760(H414), it is coarse enough to not fall through a Lee ppm and fine enough to meter Very Good. However, anything's possible.

To those who don't see anything wrong are fooling themselves. When brass flows into the ejector hole you've gone too far. And the primer fell out, the brass is ruined.

I don't really trust an electronic scale either. I have one but only use it to cross check ball powder for consistency( because its faster and I'm well below max).

If you are loading close to max pressure all components should match and have very little inconsistencies.

 

[gamestalker]

"Don't mix different head stamp brass"

This is good advice.

I had been loading for a couple years before I realized this was why pressures were so erratic. I never mix bottle neck head stamps any more.

GS