Is this overpressured? - Page 2

cw308 · April 13, 2019, 01:13 PM

F.Guffey
I check my case measurements before and after . I have not or can measure the flash hole though , l would think how hot you load the case brand all could make a difference in case changes . I load on the light side , cases don't change much , maybe 25 reloads out of a 308 case . I started using 3 different case brands 30 each and rotate each firing . At the end of the season I'll dump the lot and start over . I haven't seen much of a change on target with using 3 different case brands .

Chris

Ike Clanton · April 13, 2019, 01:29 PM

Let it cook as in sit in the hot chamber to heat up. That way I could see the affect of a temperature spike. I’ve read that this powder is temperature sensitive so I wanted to make sure I had a margin of safety for hot days or long strings if fire

cw308 · April 13, 2019, 03:40 PM

Let it cool , some shooters keep their reloaded rounds sit in the sun , causing a higher velocity in there reloads. Works the same as chambered in a hot barrel .

**Unclenick** · April 13, 2019, 03:50 PM

Now that you've pointed out the ring is soot and that the depression was an optical illusion, I am more inclined to think you may have had a primer leak. You can wipe off the bolt face with a rag and check to see if it is pitted. The primer looks fine, though. It is also curious that the edge has such a cleanly defined radial perimeter. Leaks are normally less uniform than that.

Per T. O' Heir's comment, I note the data on Alliant's site is developed with the 205M primer, which is one of the industries mildest primers. Your #41's are magnum primers with a special anvil (as compared to CCI's #450 SRM primer) that reduces their sensitivity for military-style floating firing pin guns (I assume you are shooting an AR). But magnum primers can change the pressure and velocity SD some in these small cases. By way of comparison, Federal does make their GM205MAR primer which is a reduced sensitivity version of the 205M, which would give you a closer match to the Alliant data while still have the extra slamfire resistance. Some of the newer spherical powders don't require magnum primers the way the older formulations tended to. A lot of modern standard primers now have the flame temperature-raising additives that were originally only in CCI's magnum formulations that were important to igniting the less sensitive spherical powders.

In your shoes, I would be inclined to see if I could arrange to try both primers to see if one produces better accuracy and lower velocity SD than the other and to see how groups look on the target.

Ike Clanton · April 13, 2019, 07:23 PM

I like the idea of the federal GM205MAR. The bolt face looks fine to me. I’ve attached a photo before cleaning it but it all wiped off. Upon closer inspection the ring on the brass looks more like a factory defect like some of you had stated. If it were stretching would it look that uniform? I attached a better photo if anyone cares. Again thanks for all the help this forum is a life saver.

std7mag · April 13, 2019, 08:53 PM

The Power Pro series of powder from Alliant are NOT supposed to be temp sensitive.

Marco Califo · April 13, 2019, 09:21 PM

I looked at the pictures and the primers looked normal to me: no piercing or cratering or leakage. I have done andxseen worse (using standard primers) and not worried, other than switching to magnum primers. CCI#41 are the recommended primer for 223 with ball powders, and are thicker, stronger, and less sensitive than CCI 400'S. I have had issues with non-magnum primers in hot 223 so only use 556M Russian or #41, or 450's. OHair never posts any support for his opinions stated as if they were facts. There is nothing wrong with using magnum primers in 223/556. Not absolutely necessary in all cases. But I am not about to keep both when the regular primers have zero benefit in this cartridge.

hounddawg · April 14, 2019, 08:14 AM

some of you guys sure can read a lot more into that pic than I can. All I see is a piece of Lake City brass that has been fired many times with a normal looking primer.

RC20 · April 14, 2019, 01:32 PM

Quote:

The Power Pro series of powder from Alliant are NOT supposed to be temp sensitive.

Less temperature sensitive, all have some.

**Unclenick** · April 14, 2019, 02:09 PM

If you look at Western Powder's web site, they explain temperature insensitive powders in general are stick powders that the deterrent coatings have been tweaked for. This lets you juggle how much external vs. internal perforation burning is going on. They say spherical powders, having no perforations, cannot be compensated for temperature that way. They also point out the adjustment only works well under specific conditions, so it is generally geared toward a particular cartridge or range of cartridges. Lots of folks have observed that Varget, for example, has good temperature stability in the .308 Winchester, but it doesn't exhibit that same stability in .223 Rem. Denton Bramwell found barrel temperature is a more significant factor than powder sensitivity. So these powders help some, but mainly in cold barrels. Letting a round cook will mainly defeat them.

9MMand223only · April 14, 2019, 06:01 PM

Here is a great explanation of case head swipe, or ejector swipe.
https://www.shootingillustrated.com/...se-head-swipe/

**Unclenick** · April 15, 2019, 08:23 AM

Note that as with all brass pressure signs, they will vary with how hard the brass head is in the particular brand of cartridge case involved. Some, like Federal, can be softer than others, like Lake City.

F. Guffey · April 15, 2019, 10:04 AM

Quote:

Note that as with all brass pressure signs, they will vary with how hard the brass head is in the particular brand of cartridge case involved. Some, like Federal, can be softer than others, like Lake City.

Over and over I have said it is not possible to start over with a case that has been fired 5 times but reloaders claim when neck sizing it is necessary to full length size the case to minimum length/full length size after 5 firings. I always ask how is that possible? How is it possible to start over with a case that has been fired 5 times?

Back to over the counter, new, factory loaded ammo. At one time the reloader measured the diameter of the case head before firing and then again after firing. Nothing set in stone but it was suggested the case head should expand .00025" when fired. But who measures, if the case head expanded to .0005" for the first firing it could be said the case was soft, or it could be said the load was heavy or the bullet was too heavy etc. Who knows? We do not measure before and again after. I have always thought it would be nice to have something in the chamber when I pulled the trigger; wait! There is, it is the case.

F. Guffey

F. Guffey · April 15, 2019, 10:09 AM

Before and again after, compare? Compare case head expansion with factory, over the counter new ammo with your reloads. It is not possible to fire the case over and over and over because firing the case hardens the case head so they suggested the .00025" would hold up for the first firing.

F. Guffey

cw308 · April 15, 2019, 12:20 PM

Isn't the hobby or sport called reloading . I posted before I use to go 25+ reloads on the same brand of brass using the same 30 cases . I don't load hot , which is probably the reason my fired cases have little change , I check my cases and haven't had any loose primer pockets . How would I know when case hardening would cause accuracy problems , is it in the neck area effecting bullet grip?

I have changed last year's shooting season by using three different brands of brass and rotating each range trip . My groups haven't changed in two years using the same load and bullet . Hopefully it will last until my barrel craps out , round count is 3018 to date on my 308 . Still have alittle time .

April 13, 2019, 03:50 PM	#29
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Now that you've pointed out the ring is soot and that the depression was an optical illusion, I am more inclined to think you may have had a primer leak. You can wipe off the bolt face with a rag and check to see if it is pitted. The primer looks fine, though. It is also curious that the edge has such a cleanly defined radial perimeter. Leaks are normally less uniform than that. Per T. O' Heir's comment, I note the data on Alliant's site is developed with the 205M primer, which is one of the industries mildest primers. Your #41's are magnum primers with a special anvil (as compared to CCI's #450 SRM primer) that reduces their sensitivity for military-style floating firing pin guns (I assume you are shooting an AR). But magnum primers can change the pressure and velocity SD some in these small cases. By way of comparison, Federal does make their GM205MAR primer which is a reduced sensitivity version of the 205M, which would give you a closer match to the Alliant data while still have the extra slamfire resistance. Some of the newer spherical powders don't require magnum primers the way the older formulations tended to. A lot of modern standard primers now have the flame temperature-raising additives that were originally only in CCI's magnum formulations that were important to igniting the less sensitive spherical powders. In your shoes, I would be inclined to see if I could arrange to try both primers to see if one produces better accuracy and lower velocity SD than the other and to see how groups look on the target. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 13, 2019, 08:53 PM	#31
std7mag Senior Member Join Date: June 23, 2013 Location: Central Taxylvania.. Posts: 3,609	The Power Pro series of powder from Alliant are NOT supposed to be temp sensitive. __________________ When our own government declares itself as "tyrannical", where does that leave us??!! "Januarary 6th insurrection". Funny, I didn't see a single piece of rope...

April 13, 2019, 09:21 PM	#32
Marco Califo Senior Member Join Date: April 4, 2011 Location: LA (Greater Los Angeles Area) Posts: 2,598	I looked at the pictures and the primers looked normal to me: no piercing or cratering or leakage. I have done andxseen worse (using standard primers) and not worried, other than switching to magnum primers. CCI#41 are the recommended primer for 223 with ball powders, and are thicker, stronger, and less sensitive than CCI 400'S. I have had issues with non-magnum primers in hot 223 so only use 556M Russian or #41, or 450's. OHair never posts any support for his opinions stated as if they were facts. There is nothing wrong with using magnum primers in 223/556. Not absolutely necessary in all cases. But I am not about to keep both when the regular primers have zero benefit in this cartridge. __________________ ............ Last edited by Marco Califo; April 13, 2019 at 09:28 PM.

April 14, 2019, 08:14 AM	#33
hounddawg Senior Member Join Date: March 1, 2009 Posts: 4,232	some of you guys sure can read a lot more into that pic than I can. All I see is a piece of Lake City brass that has been fired many times with a normal looking primer. __________________ “How do I get to the next level?” Well, you get to the next level by being the first one on the range and the last one to leave.” – Jerry Miculek

April 14, 2019, 02:09 PM	#35
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	If you look at Western Powder's web site, they explain temperature insensitive powders in general are stick powders that the deterrent coatings have been tweaked for. This lets you juggle how much external vs. internal perforation burning is going on. They say spherical powders, having no perforations, cannot be compensated for temperature that way. They also point out the adjustment only works well under specific conditions, so it is generally geared toward a particular cartridge or range of cartridges. Lots of folks have observed that Varget, for example, has good temperature stability in the .308 Winchester, but it doesn't exhibit that same stability in .223 Rem. Denton Bramwell found barrel temperature is a more significant factor than powder sensitivity. So these powders help some, but mainly in cold barrels. Letting a round cook will mainly defeat them. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 13, 2019, 01:13 PM	#26
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	F.Guffey I check my case measurements before and after . I have not or can measure the flash hole though , l would think how hot you load the case brand all could make a difference in case changes . I load on the light side , cases don't change much , maybe 25 reloads out of a 308 case . I started using 3 different case brands 30 each and rotate each firing . At the end of the season I'll dump the lot and start over . I haven't seen much of a change on target with using 3 different case brands . Chris

April 13, 2019, 01:29 PM	#27
Ike Clanton Senior Member Join Date: August 3, 2017 Location: Oregon Posts: 120	Let it cook as in sit in the hot chamber to heat up. That way I could see the affect of a temperature spike. I’ve read that this powder is temperature sensitive so I wanted to make sure I had a margin of safety for hot days or long strings if fire

April 13, 2019, 03:40 PM	#28
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	Let it cool , some shooters keep their reloaded rounds sit in the sun , causing a higher velocity in there reloads. Works the same as chambered in a hot barrel .

April 14, 2019, 06:01 PM	#36
9MMand223only Senior Member Join Date: November 30, 2014 Posts: 283	Here is a great explanation of case head swipe, or ejector swipe. https://www.shootingillustrated.com/...se-head-swipe/

April 15, 2019, 08:23 AM	#37
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Note that as with all brass pressure signs, they will vary with how hard the brass head is in the particular brand of cartridge case involved. Some, like Federal, can be softer than others, like Lake City. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 15, 2019, 10:09 AM	#39
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	Before and again after, compare? Compare case head expansion with factory, over the counter new ammo with your reloads. It is not possible to fire the case over and over and over because firing the case hardens the case head so they suggested the .00025" would hold up for the first firing. F. Guffey

April 15, 2019, 12:20 PM	#40
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	Isn't the hobby or sport called reloading . I posted before I use to go 25+ reloads on the same brand of brass using the same 30 cases . I don't load hot , which is probably the reason my fired cases have little change , I check my cases and haven't had any loose primer pockets . How would I know when case hardening would cause accuracy problems , is it in the neck area effecting bullet grip? I have changed last year's shooting season by using three different brands of brass and rotating each range trip . My groups haven't changed in two years using the same load and bullet . Hopefully it will last until my barrel craps out , round count is 3018 to date on my 308 . Still have alittle time .