Flattened primers: pull remaining lot and reload?

[Snowdog]

After loading some rounds with Winchester 231 (the only powder currently on hand) and Zero brand 125gr JHPs, I fired a few for function. The rounds worked great and recoil was what I expected, but upon inspection of the spent cases (which will be decapped and reloaded of course) , it appears all the primers have been somewhat flattened.

As we all know, flattened primers are potential indicators of excessive pressure. Off hand, I don't remember exact amount of 231 used, though the recipe is written on the bag they're in (at the house). I received the recipe from a reloading buddy who loads for the 9mm extensively. He gave me what he considers a "hot" load for the powder I have on hand and I stepped back .1 grains from that.

I only have 150 rounds loaded to this pressure, though I'm beginning to feel it might be smart to pull the remaining rounds and reload them with Power Pistol that I plan on buying at the range in the morning. To my knowledge, Win 231 isn't the best for achieving higher velocities.

Is it foolish to fire reloads that flatten primers, or is this indication of high pressure not necessarily the condemnation of the round being dangerous?

They will be fired from a steel-frame K9 and possibly a polymer G19 if it matters.

 

[Grumulkin]

Flattened Primers

Whether or not high pressure is indicated would be determined to some extent on the degree to which the primers are flattened. In my opinion, being guided by high pressure signs in loading for a semiauto is a bit risky both to the shooter and to the gun. I also think it's risky to rely one another person's data for a "hot" load. I really wonder what the great attraction is for a hot load. Frequently hot loads aren't as accurate as reasonable loads anyway. If you need a hot load, maybe what you really need is a bigger gun.

My advice would be to pull the bullets and in the future be guided by a reloading manual. I like advice from friends on powder choices but I ALWAYS double check the data with a reloading manual. The life/gun you save may be your own.

 

[bakert]

Like Grumulkin, I would always check anyone's advice on reload recipes with a manual. People and that includes friends sometimes get a bit carried away on hot loads and a mistake in reloading can ruin your day.

 

[Mal H]

"As we all know, flattened primers are potential indicators of excessive pressure."

The keyword is "potential". Flattened primers aren't always a good indicator of excessive pressure. Check the diameter of a fired case at the web (a little above the extraction groove) before resizing and compare it with one of your unfired rounds from that batch with the same headstamp. If the diameter has increased by any amount then you know for sure the pressure was excessive.

Can you take a picture of one of the flattened primers and post it?

I will echo Grumulkin and bakert's advice to check any load data you get from any source other than a reliable reloading data manual. To not do so is simply asking for trouble.

Also, backing off only .1 grains isn't really backing off at all. There can be a variation of .1 grains in normally safe loads during a loading run. You should have backed off about 10% which for a normal "hot" 9mm load would be in the range of .4 to .5 grains.

Be sure to post the actual load data here just to satisfy our curiosity.

 

[Bronson7]

I use Federal primers for my 45 ACP and even my moderate loads flatten the primers due to their soft material.
Bronson7

 

[ReloaderFred]

You didn't state the caliber, but I'm going to assume it's 9mm, due to the bullet weight. There will be some primer flattening with any high pressure round, and the 9mm qualifies. Compare your primers to factory fired ammunition and see what the difference, if any, is. Some rounds routinely flatten primers, such as 357 Sig and 10mm, due to the pressures involved.

I agree with the others that data should be taken from known sources and that backing off one tenth of a grain isn't really backing off at all, though Win. 231 is a very good metering powder. If you could provide the load, that would help.

You also have to realize that different bullets will have different resistance, due to the ogive, which affects the bearing surface, which in turn affects friction, which in turn affects pressure. A bullet with a short bearing surface, such as the NATO design, can take a heavier powder charge than a bullet with a long bearing surface, due to the resistance as it travels down the bore. Some jacketed hollow point designs have a longer bearing surface than jacketed round nose designs, even from the same manufacturer.

Check your loads against some loading manuals and see where it falls. If the load is over the maximum of any of them, then pull the pullets and start again with known data.

Hope this helps.

Fred

 

[The Bushmaster]

As flattened primers are common with most auto loaders I would not use flattened primers as an indicator of over pressure...If you see primer metal flow into the firing pin hole then I would look at over pressure. Glocks gives what looks like a double tap of the firing pin and is also not a sign of over pressure. Look for metal flow or ballooned cases and hard to extract or stuck cases in the chamber. If your loads conform with the load manual you will be hard pressed to have an over pressure load in 9mm, .40 or .45 ACP. I have been loading W-231 for my Wonder Nine and my Colt .45 ACP for years and my loads are near or at top loads as far as the Lyman #48 manual and Winchester load manual will allow and have had no over pressure problems...

 

[taliv]

best sure signs of overpressure are any combination of missing digits, blindness, searing pain or rapid disassembly of the firearm.

 

[Ben Shepherd]

BEFORE ANYTHING ELSE: You personally loaded these, correct? If so check for that combonation published in a current loading manual.

If it's there, you are most likely safe. If it's too hot to be piblished, pull 'em.

Also, as noted above, if you used federal primers, they are soft and flatten easily. If you used a hard primer(CCI for example) and they are flat, then you are definetely "up there" pressure wise.

 

[wrangler5]

I wondered the same thing for years - loaded rounds within the specs of the data books and still got primers that showed the tool marks on the breech face. Then I finally broke down and got a chronograph and questions were answered. Velocities tracked pretty closely to the published data (different gun/barrel meant different absolute numbers, but things were in the right ballpark.) Stopped worrying and kept loading.

Sounds like a good excuse to get a chrono. They're not all that expensive and you'll wonder how you ever got along without one.

 

[The Bushmaster]

+1 Wrangler5...................................