S&W M28-2, 357 Magnum, High Pressure, Locked Action,

the early 686's had the same problem with primer flow on the high power loads. the factory had a recall and replaced the firing pin and pin hole insert. maybe s&w will do the same for the m28. other than a thicker primer cup, that seems the only solution.

luck,

murf

I think it looks like bad primers. Have you tried some CCI or Remington? I have had some disappointing experiences with Winchester components (and rim fire ammo) over the past few years. In the past I have loaded .357 Magnums with Accurate No. 9 with heavier charges and similar bullets and CCI primers without issue.

AJC1 said:

My system is to use .2 grain increments for testing pistol. I do the same in 223 and I use .3 grain most time in 308.

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I don’t really have a “system” other than gathering as many data points as I can, resource or first had but I prefer to learn from the mistakes of others.

Some stuff .2 gn is the difference between MAX and MIN.



Other stuff like 50 BMG, with a ~220gn charge, .2 gn is nothing.

243winxb said:

Happened again today.

At the starting load of 11.2 gr, No. 9. Fired 18 rounds. The 16th round locked the action. Primer flowed into firing pin hole (hammer nose). Rounds 17 & 18 blanked the primers. Bottom left 3.

Same components used.

Brass seem to show a mark from the recoil shield . All brass extracted normal.

Needs a complete investigation, clean and fire with 13.0grs 2400, for starters. View attachment 1079169 View attachment 1079170

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Accurate 9 has a faster recoil impulse than 2400 so 2400 should be a little easier on the brass than AA9, may not show up as profound as AA9 problem is.

I'm wondering about the looks of the hammer nose dents on the brass. It may be lighting conditions but some of the dents look deeper than other.
Powder not burn consistantly? Has your hammer nose been tuned in to the gun after it was staked on the hammer.
When mine was replaced we had to work it down a little because the pin was a little to long when it was new. It would pierce a primer now and then and with the harsher recoil of some powders and loads.
I also noticed that the dents are everywhere from center of primer to off to the side of primer and I don't remember either one of my 28s ever doing that.
The strikes were dead center of the primers. I may just not be remembering correctly.
I'm not in a position to test my guns for that because I'm laid up right now. Trying to go from memory. The dents don't look round either.

Are these things just lighting conditions or am I seeing an accurate view of the case heads?

Not really sure what to think of the primers that look deeper than others. I would also lean toward the powder not burning consistently on that one to start with but if the hammer nose is striking off sides of the bushing it also could be inconsistent with the strikes. Any side to side movement of the hammer?

Just trying to wrap my head around this. Definitely try the 2400 though and see what shakes out of that.

243winxb said:

The strain screw had backed out, causing lighter then normal strikes. The hammer bounce makes the indent in the primer, oval.

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I just saw your previous post regarding the strain screw, and then this one. And as soon as I read "strain screw" it clicked.

I just had an issue with my new 686, and the strain screw backing out was the cause. Light strikes, and primer flow into the fire pin hole. No pierced primers for me, but between the primer flow and the extractor rod simulataneously beginning to unscrew, I had an interesting time.

I'm glad you figured it out!

jmorris said:

I don’t really have a “system” other than gathering as many data points as I can, resource or first had but I prefer to learn from the mistakes of others.

Some stuff .2 gn is the difference between MAX and MIN.

View attachment 1079238

Other stuff like 50 BMG, with a ~220gn charge, .2 gn is nothing.

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I've learned to qualify my statements here because of exactly this reason. If using my plan for my cases makes sense then why not... the smallest case I currently load is 38spl.... if loading a 25acp then you may need different rules...

Can you use them for normal loads instead of magnum loads?
Good luck with Winchester. Hope they do something for you.

243winxb said:

I know not to up the powder charge 9/10 of a grain at a time with ball powder, but…

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The knowledge doesn’t do much good when we don’t follow it.

When I started “maximum” was something worked up to, if everything seemed OK, in the particular firearm, working up. The trend over the last couple of decades seems to indicate more people just jump right to WFO and the books seem to have been adjusted accordingly.

243winxb said:

Is Accurate #9 powder, a position sensitive powder, in 357 mag?

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In the updated 5th edition Accurate loading guide you uploaded photos from, the 4th paragraph of the introduction starts with,



Oddly enough, in that guide they don’t have 357/#9 data below 150 grain bullet, the current western guide goes down to 110.

https://ramshot.com/wp-content/uploads/2020/08/WesternPowdersHandloadingGuide8.0_WEB.pdf

From the 10th paragraph of the intro of the same guide.

Walkalong said:

I never had good luck with AA # 9 in .357 Mag, does great in .44 Mag.

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My experience as well. My testing had H110 my choice over AA#9 and Ramshot Enforcer for 158 grain .357 mag and AA#9 my choice over H110 and Enforcer for 240 grain .44mag.

243winxb said:

Is Accurate #9 powder, a position sensitive powder, in 357 mag? Anyone checked with a chronograph? Ty.

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I do believe @AJC1 has done alot of testing with #9...............maybe if we call him out...................

Soonerpesek said:

I do believe @AJC1 has done alot of testing with #9...............maybe if we call him out...................

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Bring out the Bat signal!

243winxb said:

Is Accurate #9 powder, a position sensitive powder, in 357 mag? Anyone checked with a chronograph? Ty.

Standard or magnum primers used?

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For what it’s worth, I ran a 10 shot string out of my 6” 27-2 with 13 grains of #9 and magnum primers with a 158 grain Lee RNFP. My notes show average velocity of 1210 fps, Max deviation 79 fps and a standard of 32 fps.

243winxb said:

To light of a powder charge may be an issure with ball powder.

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I have read folks warn about working below minimum with H110/W296.

I don’t know personally. Every time I think about setting up to measure pressure, to learn more about one thing or another, something else uses up my time.