Author Topic: Definetly a newbie question (Read 1331 times)

tipiguy · « **on:** September 04, 2003, 01:50:46 AM »

I have heard people talk about flattened primers as a sign that your load is getting too hot. My assumption was that the primer becomes flat on the outside and does not show where the firing pin hit. Is this correct?

Thanks.
tipiguy

Mikey · « **Reply #1 on:** September 04, 2003, 03:54:05 AM »

tipiguy: that's pretty close. You will be able to tell where the firing pin hit but if that area is flattened too, your pressures are way up there. Stay safe. Mikey.

Graybeard · « **Reply #2 on:** September 04, 2003, 05:38:14 AM »

The ONLY thing a flattened primer really tells you is that "your primer is flat". Beyond that you can really be certain of NOTHING.

There are just too many varibles in the mix to be sure that excessive pressure is the cause. And just because the primer is not flat is NOT reason to assume the pressure is NOT excessive. There are no visible signs you can use to determine what is and what is not a safe load.

Stick to the book loads. That's the best you can do unless you have pressure measuring equipment. If you use the same components that the book used except for lot numbers which will likely always be different then your chances of the load being safe as as good as you'll get minus your own pressure measuring equipment.

GB

Lee D. · « **Reply #3 on:** September 04, 2003, 05:45:43 AM »

With my 6.5x55 I get sharp edged primers even with fairly mild loads. The only surefire indication I have ever seen for overpressure was blown cases, defintely my fault and a long story about how it came to happen, but it won't happen again.

grizz · « **Reply #4 on:** September 05, 2003, 03:53:34 AM »

Tipiguy,

There are many signs of pressure.. Sticky bolts, extractor markings,flat primes, Primer pockets getting loose etc... Even if you stick to the books you still could run into problems.. Ever take a look at a old load book and compair it to a new one? Some loads in the older books are hotter then the newer ones.. Unless you are using the exact same gun/componets used when they made the book you cant be sure if those loads are gonna work in your gun the same.. Every gun is different but as long as you start with what the book has listed as a minimum and work up slowly to the max whatching for the signs of pressure you will be fine.. For instance a friend of mine and I both a have a 6.5/300 WWH.. Both shoot 139-142gr bullets both use H-870 powder but I shoot 85-87gr of H-870 when he cant even reach 82gr without signs of pressure.. When he reaches 82-83 gr he gets sticky bolts flat primers and extractor margins.. I dont show any of these signs... Every book I seen for that caliber recommends loads from 78-87gr of H-870.. Just goes to show that differnet guns handle pressure differntly.. Another thing that you cant always assume is the velocity you are getting to.. I have seen many times where a book will say with this load you will get this velocity that just isnt the case that I have seen.. I have reached listed velocity with with smaller loads and same bullet as what the book has listed.. They are close and they are the best referance material you can get but always remember guns will be different and knowing what signs to look for will ensure safe shooting.....

grizz

grizz · « **Reply #5 on:** September 05, 2003, 04:06:37 AM »

Tipiguy,

Here is a photo that is the best i can find to show you flat primers.. From left to right... Normal, slight pressure, Extreame pressure...

grizz

T/C nimrod · « **Reply #6 on:** September 05, 2003, 08:09:57 AM »

grizz - Are those cases fired with the same load?

1GLOCK · « **Reply #7 on:** September 05, 2003, 08:37:07 AM »

I think grizz has it right. Take the 45-70 trapdoors for example. An overpressure load will turn it into a grenade before any signs of excessive pressure shows on the case. Just stay within the books guidelines for each load and work up slowly and watch out for worn out casses and older guns that cant handle what modern guns can and youll be fine.

grizz · « **Reply #8 on:** September 05, 2003, 11:59:00 AM »

T/C nimrod,

I cannot verify if they are the same loads or not.. I was just browsing and found that pic and it showed what good primers and flat primers looked like.... I just wanted a example to show Tipiguy what to look for...

grizz

Duffy · « **Reply #9 on:** September 05, 2003, 08:55:12 PM »

I have a box of Frontier 30-06 brass that my bro-inlaw gave me and most of them look like item C in the pic's that grizz posted. Funny thing is that they were FACTORY loads and that's what they looked like after being shot out of his old Mauser.

Full length sizing of the brass will usually show a more flattened primer than brass that has been neck sized only.
The full length sizing gives more room for the primer to back out during firing and usually flattens it more when it reseats it. That's another reason why it can be a confusing indicator for pressure.

Ryan

grizz · « **Reply #10 on:** September 06, 2003, 05:18:19 AM »

Hrmmm If I had factory loads that made primers that flat I would NOT be shooting them.... If that load was any hotter it would look like this or worse...

But that is very extreame pressure...

Quote

Full length sizing of the brass will usually show a more flattened primer than brass that has been neck sized only.

I can fully understand that.. But FL sizing is NOT the only thing that will cause the primer to back out either.. They are either backing out because of to much pressure blowing the primer out or the primer pocket is to loose to begin with and should not be shot again... To much pressure will cause the primer pockets to expand and will show flat primers causing it to look like high pressure... If this is happining after the first reload I say your alittle hot.. But on the other hand if its after 5-8 reloads the cases are just worn out... That just goes to show you cant always assume that because the primers are flat that your to hot but within the first firing when workin up loads you are getting any of these signs I would try backing off alittle bit and try again.... just my 2 cents..

grizz

Duffy · « **Reply #11 on:** September 06, 2003, 06:28:52 AM »

I should have added that while most of the primers looked like item C they were many like B also. Still hotter that anything I would have continued to fire.

I said he was my brother in-law, I didn't say he was smart.

If it takes high pressures back primers out then why do they back out when you fire a primer only? When shooting the Speer target plastic bullets in 45 acp brass you have to enlarge the primer hole so they dont back out and hang up on the firing pin. These use no powder, only primer power. Unless they are crimped in they all back out some when fired and are reseated when the case thrusts back. My thinking is that in the hotter loads they are forced out farther by the higher pressure pushing them back and also expanding the case head. Have to throw in action flex here too. Then they aren't able to be seated back in properly when the case moves back either by being cocked, carbon deposits or the case head has sprung back some. This is where the nice swaged look comes from.
My 2 cents.

Ryan

Graybeard · « **Reply #12 on:** September 06, 2003, 10:16:00 AM »

Like I said above. The only thing a flat primer tells you for sure is you have a flat primer. It is not a good indicator of what the pressure was in that load. Way too many other reasons than pressure for primers to be flattened on firing.

Ya might have grease or oil in the chamber or on the round. Ya might have excessive head space or not enough. You might have an over size chamber.

Flat primers just don't necessarily mean high pressures. Altho when one looks like C I'd sure think high pressure as something sure ain't right.

I shoot the Hornady ammo mentioned in my rifle with no such flattened primers. They test it regularly for pressure. I'd bet the problem is the rifle not the ammo.

GB

grizz · « **Reply #13 on:** September 06, 2003, 12:50:23 PM »

I agree that there are many things that can cause flat primers especially if you are shooting factory loads adn are getting them.. More then likely you are having headspace problems... But to go as far and say that flat primers are not a sign of pressure is crazy!!!!! Lets say this for example.. Your working up a load for um lets say a 243Win shooting 100grainers.. Max load for 100's for IMR-4350 is 42.3gr according to my Sierra 50th Annivesary book and min in 36gr... I would start at 36gr and work up.. Now if @ 36gr you see flat primers I would say its a gun issue and not a pressure problem.. Now lets say we get to 41gr testing @ .5gr increments and now all of a sudden we are getting flatened primers and the previous grains are not showing any issues at all... This is a obivous sign of pressure!! If your having guns issue they will tend to show it early not when you are almost @ max.. So lets say you went ahead and shot a round that has 41.5 gr and the primer is even more flat now and also we have ejector markings on the case head this is telling you something and its not that the primer is flat its letting you no you are starting to show pressure and you should back off.....

There are many signs of pressure you may not get a flat primer before your bolt sticks or any other signs but dont be fooled flat primers CAN be a sign of pressure...

grizz

Graybeard · « **Reply #14 on:** September 06, 2003, 06:24:26 PM »

I like what JD Jones has to say about pressure. If the bullet cleared the barrel that's a pretty good sign of pressure.

Now how much pressure that is the question. This is all I'm saying, "there are NO RELIABLE indicators of when you cross the safety threshold". If you load only a primer and a bullet and no powder you still have "pressure". Pressure is a constant you can depend on. If the primer fires there will be pressure.

BUT how much? Ah that is the sticky point. Without pressure measuring equipment you have no clue.

Yes a sticky bolt is a pretty good indication all is not well. So is ejector marks on the case head. But are they REALLY telling you the load is excessive in pressure? Maybe. Probably even. BUT most likely you were already over way before then.

It is NOT crazy to say flatten primers is NOT an indication of excessive pressure. To say it isn't a sign of pressure at all isn't crazy as it is certain you already have pressure every time the cap fires. How much pressure and is it safe or not cannot be determined by looking at primers.

Now if you have a box of primers (1000 or more let's say) and if you've been loading those primers in the same lot of cases and using them in the same gun and you've not been getting any flatten primers and now for some reason you all of a sudden come up with a flat primer? Well I'd stop and figure out why. That just might be an indication of some pressure excursion from the norm you've been looking at.

These things have been proven by more than one of the modern technical folks who actually use pressure measuring equipment and compare the actual pressure to the first time these OLD methods indicate pressure might be excessive. Results varied from getting excessive pressure sights or apparent excessive pressure signs when loads were well below SAAMI specs to getting none with loads were blue pill proof pressure.

Do not rely on the various visual signs of pressure to allow you to continue dumping powder in a case. Stop at the book max assuming you are using all the same components as them except for lot #s. Otherwise have a bunch of books and take the average from them and use that as your max. Even better buy a chrono and when you reach the velocity the book says they got at max STOP. No matter what the amount of powder stop. Also when the rise in velocity from a grain increase in powder ceases to be linear stop. None of these are absolutes either but are better than the visuals of looking at primers and hoping to feel a sticky bolt which might only be dirty.

Again I say the ONLY reliable thing a flat primer tells you is the primer is flat. That it fired has already told you pressure exists.

GB

grizz · « **Reply #15 on:** September 06, 2003, 07:38:11 PM »

Quote

Now if you have a box of primers (1000 or more let's say) and if you've been loading those primers in the same lot of cases and using them in the same gun and you've not been getting any flatten primers and now for some reason you all of a sudden come up with a flat primer? Well I'd stop and figure out why.

Lets say we made it 3/4 of the way through that box of primers still using the same brass and powder charge now we see a flat primer.. I would say that case's primer pocket is getting loose from all the previous firings.. Since there really is NO way to tighten a primer pocket you are bound to run into this problem after a few firings.. Would that be a sign of high pressures?? No I would say not... I would say its a sign of your brass starting to weaken..

Quote

It is NOT crazy to say flatten primers is NOT an indication of excessive pressure.

Explain to me this in my example

Quote

Your working up a load for um lets say a 243Win shooting 100grainers.. Max load for 100's for IMR-4350 is 42.3gr according to my Sierra 50th Annivesary book and min is 36gr... I would start at 36gr and work up.. Now if @ 36gr you see flat primers I would say its a gun issue and not a pressure problem.. Now lets say we get to 41gr testing @ .5gr increments and now all of a sudden we are getting flatened primers and the previous grains are not showing any issues at all...

How can this NOT be a sign of high pressure?

? I can tell you why it IS a sign of high pressure..Why?? Because at 40 and 40.5 there wasnt as much pressure as there was at 41gr.. At 41gr there was enough pressure to cause the primer to hit the bolt face harder causing the primer to become flat... Then when you went to 41.5gr you are now hiting the bolt face hard enough to get the ejector markings as well.. Why??? Because of HIGHER pressure's... Now would it be safe running @ 41gr sure you prolly are as long as tempertures dont raise but you wont catch me doing it... After a few more firings in that brass it will cause the primer pocket to expand to the point where either the primer will simply wont stay in the case or your pocket is loose enough to cause you to get a blown primer...

Im not saying there isnt better ways to test for pressure all the way's mentioned are very good indications.. Just because a book says this is max doesnt mean its max for YOUR gun... I dont own any pressure measuring equipment so I go by signs of pressure.. I do own a chrony and that is a very good factor as well but I disagree on stoping when you reach a velocity faster then whats listed... Reason?? Simple you are NOT shooting in the same spot that gun was tested at... Was it a 60° or a 90° day?

What altitude were they at?? You dont know this at all... All can play a big facter in what your velocity is goin to be... Now if you add 1 more grain and the velocity did NOT increase at all from your previous load is that a sign of excessive pressure??? Could be... But it could also be that you run out of bbl lenght to burn that much powder as well.. Now is it a good idea to drop back a gr... Absolutly there is no sense in running the extra gr of powder your not gaining anything except higher pressure for NO reason at all..

Like I said earlier the books are one of the best "referance" material you can get but they are not always the final say...

grizz

John Traveler · « **Reply #16 on:** September 07, 2003, 05:02:45 PM »

Hey, Fellas!

I've read and re-read this string enough to realize that Graybeard is being misunderstood here.

He is CORRECT in stating that "reading" flattened primers is NOT a good indication of high pressure in handloads!

Some of us have spent considerable time in ballistics laboratories with the latest in pressure guns, instrumentation, sensors, chronographs, etc, and BELIEVE me, flattened primers appearing during load developement MAY or MAY NOT indicate unsafe excessive pressure excursions.

If carefully done, measuring FACTORY case head expansion and watching for flattened primers MAY be good indications of excessive pressure. Not always!

More on this later. I gotta run.

John

T/C nimrod · « **Reply #17 on:** September 08, 2003, 01:20:19 AM »

Grizz - (Hopefully this won't mysteriously disappear). The reason I asked about the primer picture: That would have been a perfect example of how different headstamps affect pressure. Would have been a pretty extreme example, but anythings possible.

grizz · « **Reply #18 on:** September 08, 2003, 03:21:38 AM »

Quote

Some of us have spent considerable time in ballistics laboratories with the latest in pressure guns, instrumentation, sensors, chronographs, etc, and BELIEVE me, flattened primers appearing during load developement MAY or MAY NOT indicate unsafe excessive pressure excursions.

I agree that it MAY or MAY NOT be a sign of high pressure... This is what I have been saying... There are many different reasons for a primer to be flat but HIGH pressure is deffinatly one of them period!!

grizz

High Brass · « **Reply #19 on:** September 09, 2003, 03:14:39 AM »

Different manufacturers of primers have different primer cup hardness(if that's the correct word). A win. primer may "flatten" or be softer than a rem. or vice-versa. John Barseness wrote an interesting article in Handloader magazine discussing this. I cannot recall what issue but it pointed out a lot of things that I never thought of. Of course you can always use a rule that I go by....in handloading when in doubt, don't do it!

Graybeard · « **Reply #20 on:** September 09, 2003, 01:13:58 PM »

Griz and TC nimrod. You are both arguing just for the sake of arguing with me to see if you can piss me off. Trust me you're real close. Our discussion on this is at an end. If you have anything of value to add do so. Don't post just to piss me off again however. You won't like the result.

GB

Dave in WV · « **Reply #21 on:** September 09, 2003, 07:42:57 PM »

I had a Rem 760 that flattened primers with a very mild load much less full power factory ammo. By the time you have pressure leakage around primers, pierced primers, primers flowing into the ejector hole/groove, you are probably above a proof load. When working up a load I observe the "soot" on the case neck. If I stop gettting any soot on the outside of the neck I stop increasing powder. It's not a given truth of high pressure but I figure it keeps me out of trouble. Dave

T/C nimrod · « **Reply #22 on:** September 10, 2003, 01:46:01 AM »

I thought this was a discussion. The argument is mine in regards to deleted posts that contained valid information. :?

Tipiguy - After doing some group analysis from Project 41 last evening, I believe I have a perfect situation that applies to your question. Here's my situation: I have a ramp of Blue Dot powder that went from 10.1 grains to 13.5 grains in .4 increments. (13.5 is one load below published max) Starting load of 10.1 grns. showed .0008" case expansion, zero primer appearance change, and low recoil (as compared to previous shooting sessions). The load of 13.5 grns. shows a slightly discolored primer (under a magnifying glass), slightly straightened primer edges, a .0015" case expansion, and noticeably more felt recoil. It was at this load that I printed the best 5 shot group @ 100 yards (as compared to the previously fired loads with the same components). By the best group I mean the smallest spread, 2nd lowest standard vertical deviation (.27"), lowest standard velocity deviation (9fps), and lowest velocity spread (12fps). Now, would you proceed or stop here?

grizz · « **Reply #23 on:** September 10, 2003, 05:08:33 AM »

Is this not what forums are for to see what other people's opinions are?? If i was trying to piss me off trust me I would NOT beat around the bush to do it... I disagree with your statement that flat primers just tell you primers are flat and im intitled to my opinon.... You made a statement about using a 1000 primers and makeing it through half of them then all of a sudden you get a flat one.. I in returned answered that with facts on why it is NOT a sign of pressure because after a bunch of firings you can get loose primer pockets and I also stated that I felt if this was done in load development and within the first firing testing loads that it could very well be to much pressure causing the primer to flaten and tried to use a good example... I know there are better ways to measure pressure but not all of us can afford that high dollar equipment so we go by what signs we can go by and we use all of them to our advantage.. I have been goin by these signs for some 18 years now and never and I repeat NEVER had a bad experiance using them.... Take my statements any way you will it doesnt matter to me.. Just because you are the site owner/admin doesnt mean i cant disagree with you.. And to be truthfull if this is how you react to everyone that has a differnt opinion then yours its no wander this site is slowing down...

grizz

ButlerFord45 · « **Reply #24 on:** September 11, 2003, 01:52:12 AM »

This thread has strayed from the topic and is rapidly turning into a pissing contest. Everyone is entitled to their opinion and is welcome to voice that opinion, but please do so with a little diplomacy and courtesy without demeaning others ideas.