Forums46
Topics537,784
Posts9,729,104
Members87,042
|
Most Online25,604 Feb 12th, 2024
|
|
|
Over pressure
#5587404
02/07/15 05:43 AM
|
Joined: Aug 2013
Posts: 2,030
spg
OP
Veteran Tracker
|
OP
Veteran Tracker
Joined: Aug 2013
Posts: 2,030 |
Got into a interesting conversation with a reloader friend after he brought me some of his fired casing to deprime because he broke his dye. I noticed the primers had mild cratering and I asked him if he was aware he said yes thats how they have always looked. Then I told he's loading to hot and of course disagreed. Any of you load this hot and is it safe
|
|
|
Re: Over pressure
[Re: spg]
#5587415
02/07/15 06:08 AM
|
Joined: Nov 2007
Posts: 9,517
RiverRider
THF Trophy Hunter
|
THF Trophy Hunter
Joined: Nov 2007
Posts: 9,517 |
Cratering can appear for reasons other than excessively hot loads.
"Arguing with you always makes me thirsty." -Augustus McRae
|
|
|
Re: Over pressure
[Re: spg]
#5587750
02/07/15 04:01 PM
|
Joined: Aug 2011
Posts: 342
Capt Craig
Bird Dog
|
Bird Dog
Joined: Aug 2011
Posts: 342 |
There is no good reason to load hot. IF you can't get the round to do what you want, use a different caliber.
|
|
|
Re: Over pressure
[Re: RiverRider]
#5587866
02/07/15 05:24 PM
|
Joined: Oct 2006
Posts: 4,200
dawaba
Extreme Tracker
|
Extreme Tracker
Joined: Oct 2006
Posts: 4,200 |
Cratering can appear for reasons other than excessively hot loads. A loose fitting firing pin in the bolt face will cause cratering, even if the pressures are normal. Soft primer cups can too. Are there any other signs of excessive pressure? If your friend's load is published and is producing the proper velocity for the cartridge, it's likely not over-pressured. Could you share the load and velocity he's getting?
"For every complex problem there is an answer that is clear, simple.....and wrong." H. L. Mencken
|
|
|
Re: Over pressure
[Re: spg]
#5587918
02/07/15 06:19 PM
|
Joined: Aug 2013
Posts: 2,030
spg
OP
Veteran Tracker
|
OP
Veteran Tracker
Joined: Aug 2013
Posts: 2,030 |
|
|
|
Re: Over pressure
[Re: spg]
#5587938
02/07/15 06:32 PM
|
Joined: Sep 2006
Posts: 32,484
kmon11
junior
|
junior
Joined: Sep 2006
Posts: 32,484 |
Primers are often what are looked at for high pressure but with the different thicknesses and hard or soft primers it is not the most reliable indicator of pressure. But by the time some pressure signs start showing up pressures are already well above SAAMI Specs. Flattened, cratered, blown or loose primers do indicate pressure, but not totally reliable and sometimes can be just what gets you looking at what else could be the real cause. Shiny spots on the case base, case expansion, sticky bolt lift.... are generally all high pressure signs that you really do want to repeat IMO.
Lacking pressure test equipment which most of us do, a chronograph is one of the best indicators of where we should stop adding more powder to the case. There is a correlation of velocity and pressure and if velocity is high for the round so is pressure.
Excessive oil in the chamber, head space issue are a couple more that can cause primer cratering without excessive pressure.
lf the saying "Liar, Liar your pants on fire" were true Mainstream news might be fun to watch
|
|
|
Re: Over pressure
[Re: spg]
#5587959
02/07/15 06:46 PM
|
Joined: Aug 2013
Posts: 2,030
spg
OP
Veteran Tracker
|
OP
Veteran Tracker
Joined: Aug 2013
Posts: 2,030 |
I'm no expert but know if the primer is cratering the charge is to hot or the primer hole is partially restricted.
|
|
|
Re: Over pressure
[Re: kmon11]
#5588042
02/07/15 07:48 PM
|
Joined: Dec 2008
Posts: 41,160
J.G.
THF Celebrity
|
THF Celebrity
Joined: Dec 2008
Posts: 41,160 |
Primers are often what are looked at for high pressure but with the different thicknesses and hard or soft primers it is not the most reliable indicator of pressure. But by the time some pressure signs start showing up pressures are already well above SAAMI Specs. Flattened, cratered, blown or loose primers do indicate pressure, but not totally reliable and sometimes can be just what gets you looking at what else could be the real cause. Shiny spots on the case base, case expansion, sticky bolt lift.... are generally all high pressure signs that you really do want to repeat IMO.
Lacking pressure test equipment which most of us do, a chronograph is one of the best indicators of where we should stop adding more powder to the case. There is a correlation of velocity and pressure and if velocity is high for the round so is pressure.
Excessive oil in the chamber, head space issue are a couple more that can cause primer cratering without excessive pressure.
Wise man.
800 Yard Steel Range Precision Rifle Instruction Memberships and Classes Available
|
|
|
Re: Over pressure
[Re: spg]
#5589083
02/08/15 06:18 PM
|
Joined: Sep 2009
Posts: 18,935
ChadTRG42
THF Celebrity
|
THF Celebrity
Joined: Sep 2009
Posts: 18,935 |
It also depends on which primer he is running. I don't look at the primer any longer as an indication of pressure. It does or can easily give you a false indicator of pressure. The bolt head and firing pin opening can make a primer look like a hot round when it's not. The 2 main things I look at are #1- sticky bolt lift and #2- shiny spots on the case head (from the bolt or the extractor). Next would be the chrono numbers, but not always.
|
|
|
Re: Over pressure
[Re: spg]
#5590323
02/09/15 02:37 PM
|
Joined: Nov 2011
Posts: 3,633
DStroud
Extreme Tracker
|
Extreme Tracker
Joined: Nov 2011
Posts: 3,633 |
I had a Rem 700 17 rem that showed cratered primers no matter the load until I had Greg Tannel bush the firing pin NO more cratering. Primers are not reliable indicators as above posters have said
"Anyone taking up handloading necessarily plays with unknown factors and takes chances. But so does anyone who drives a car,goes to a cocktail party,eats in a restaurant,or gets married."
Jack O'Connor 1963
|
|
|
Re: Over pressure
[Re: spg]
#5590356
02/09/15 03:04 PM
|
Joined: Oct 2004
Posts: 39,534
redchevy
THF Celebrity
|
THF Celebrity
Joined: Oct 2004
Posts: 39,534 |
Had cratered primers in loads that were well below max on brass that was past its prime.
It's hell eatin em live
|
|
|
Re: Over pressure
[Re: spg]
#5591594
02/10/15 02:34 AM
|
Joined: Aug 2006
Posts: 925
BigDad
Tracker
|
Tracker
Joined: Aug 2006
Posts: 925 |
Primer cratering is not a reliable indication of excessive pressure. I had a Model 70 in 270 WIN that always cratered primers even with light loads.
Joe
|
|
|
Re: Over pressure
[Re: spg]
#5594320
02/11/15 07:13 PM
|
Joined: Jan 2012
Posts: 9,273
blackcoal
THF Trophy Hunter
|
THF Trophy Hunter
Joined: Jan 2012
Posts: 9,273 |
Not wishing to start an argument, and the above posts are correct in possible problems, did I miss where the OP said this was occurring with a bolt action?
Assuming there is actually excessive high pressure, another possibility could be in the depth of the bullet seating.
Another possibility no one has mentioned is the powder could have been below the minimum charge.
The Greatest Enemy of knowledge is not ignorance, it is the illusion of knowledge.--Stephen Hawking
|
|
|
Re: Over pressure
[Re: blackcoal]
#5594367
02/11/15 07:43 PM
|
Joined: Oct 2004
Posts: 39,534
redchevy
THF Celebrity
|
THF Celebrity
Joined: Oct 2004
Posts: 39,534 |
Another possibility no one has mentioned is the powder could have been below the minimum charge. Have also experienced this with starting loads.
It's hell eatin em live
|
|
|
Moderated by bigbob_ftw, CCBIRDDOGMAN, Chickenman, Derek, DeRico, Duck_Hunter, hetman, jeh7mmmag, JustWingem, kmon11, kry226, kwrhuntinglab, Payne, pertnear, rifleman, sig226fan (Rguns.com), Superduty, TreeBass, txcornhusker
|