Pressure Signs WAY before max charge ??

David Emerson

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Jan 1, 2020
Messages
1,095
Location
Drayton,ND
I've shot/Reloaded 7-08 139-140 gr for 10 years. Trying a 120gr load for Wifey. Using H414, H4350 and RL15. Started LOW/Med loads. I should be able to get 2900 easy and up to 3200. H414 44.2gr, RL15 42gr and 4350 47gr. All are Middle Loads. New Starline Brass, Win Primers and Nosler 120 B-Tips. 4350 gets 2520fps and FLAT PRIMERS....H414 get 2720 and FLAT PRIMERS...RL15 @ 2650 Yea, you guessed it ...FLAT PRIMERS. I'm shooting .02 off lands. What is going on? If I were 400 FPS faster, I'd understand. I have NO heavy bolt lift...or other pressure signs... Seems every load..( 300 BLK OUT...6.5 Gren...5.56 Ect).. I have used Win Primers with the past 6 months has been "HOT"...not in FPS but plenty pressure signs. Has anyone else had issues with Win Primers? Maybe try CCI, Rem or Fed ?? Rifle is a Marlin X7. I'm at 3700' Elevation. Rifle is grouping from 2" down to .75 (Faster the better)
Maybe bad Chrono ?? Showing wrong speed??? Thoughts Please
Too much headspace will flatten primers. In a 24 inch barrel 3000 is about it with a 120. Use a dial caliper just ahead of the extraction groove. When your brass grows a .0005 you are at pressure. Using primers to read pressure is not too good.
 

Sid Post

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Jul 27, 2007
Messages
169
Location
Texas, USA
Light loads can go from a nice burn to an explosion.

With African bolt actions, people have been known to load light lights for recoil control and only to end up hand grenading their rifle. If loading light loads, you really should consider adding some case filler to limit the oxygen so you get a nice flame across the powder and not a detonation.
 

TheBoctor

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Joined
Oct 11, 2018
Messages
65
Location
NOCO
Any other pressure signs or only flattened primers? No ejector marks or anything? Tried pushing it further until you see other, more reliable signs?

I don't worry much about what the primers look like if the rest of the case head looks good. I've had them get flattened several grains before theoretical max and the first hint of ejector marks, especially on the first firing of brass.
 

Tommo64

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Joined
Nov 29, 2018
Messages
131
Location
Adelaide
Flattened primers alone without any other signs suggests it may not be a pressure issue. The low velocity readings also support this I would suggest. As others have suggested, try again with once fired brass, maybe neck sized only and see what happens. If the Win primers are still flattening out, try a different brand. Maybe seat a little deeper (are you certain you are .02 off lands or are you inadvertently jamming them?). Change one variable at a time and check the results.
 

bubbaonpc

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Oct 4, 2015
Messages
103
Location
Creston, North Carolina
Thank you all !! Gonna neck size once shot...lil higher load..same primer...seat bullet but deeper and shoot..then change primer and repeat. I've reloaded hundreds of 139's and 140's with awesome results "Different rifles"
This marlin is really testing me ! I'll post results. Thanks again to each of you for your time !
 

bubbaonpc

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Oct 4, 2015
Messages
103
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Creston, North Carolina
One thing to check that hasn’t been mentioned, neck clearance.

Can you drop a bullet into a fired case?
What is the outside neck measurement of a loaded case and a fired case?

I’ve seen on multiple occasions where you get pressure signs very early with too little neck clearance. The brass can’t fully release the bullet before pressure builds. This has shown me pressure well before it should and slow speeds.
Great thought ! Hadn't crossed my mind. Thank you
 

whirlwindjml

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Joined
Aug 23, 2009
Messages
344
Location
Rathdrum Idaho
Once I was loading 300 ultra mag with win primers and having huge problems. I was trying to chrono and get things all ready for hunting and have a laminated dope chart. I also load for a friend. Things were all over the place on velocity and nothing had really changed much from my data book note. Trip after trip backing loads down and blowing holes through the primers.

Staring at the bench....
frustrated days later.... my eyes focused on the primers and it hit me. I had a stray pack of win pistol primers I didn't know I owned. (Maby from my friend shopping tripp) Those.are do doo because they are thinner. The pack blended in with the others. I must have grabbed them during the Obama craze because I dont even load pistol.

Just a thought. Clear the bench and Clean the gun. Examine everything as you get it back out. We are human so sometimes we miss something. Hope ya figure it out safley.
 

bubbaonpc

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LRH Team Member
Joined
Oct 4, 2015
Messages
103
Location
Creston, North Carolina
Once I was loading 300 ultra mag with win primers and having huge problems. I was trying to chrono and get things all ready for hunting and have a laminated dope chart. I also load for a friend. Things were all over the place on velocity and nothing had really changed much from my data book note. Trip after trip backing loads down and blowing holes through the primers.

Staring at the bench....
frustrated days later.... my eyes focused on the primers and it hit me. I had a stray pack of win pistol primers I didn't know I owned. (Maby from my friend shopping tripp) Those.are do doo because they are thinner. The pack blended in with the others. I must have grabbed them during the Obama craze because I dont even load pistol.

Just a thought. Clear the bench and Clean the gun. Examine everything as you get it back out. We are human so sometimes we miss something. Hope ya figure it out safley.
I spent 2 hours today doing just that. Loading for 7-08...308...5.56...243 and Blk out...my room looked like tornado hit it. Now I'm starting clean.
 

RYEWSKY25284

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LRH Team Member
Joined
Jan 23, 2014
Messages
492
Location
Albuquerque,NM
I've shot/Reloaded 7-08 139-140 gr for 10 years. Trying a 120gr load for Wifey. Using H414, H4350 and RL15. Started LOW/Med loads. I should be able to get 2900 easy and up to 3200. H414 44.2gr, RL15 42gr and 4350 47gr. All are Middle Loads. New Starline Brass, Win Primers and Nosler 120 B-Tips. 4350 gets 2520fps and FLAT PRIMERS....H414 get 2720 and FLAT PRIMERS...RL15 @ 2650 Yea, you guessed it ...FLAT PRIMERS. I'm shooting .02 off lands. What is going on? If I were 400 FPS faster, I'd understand. I have NO heavy bolt lift...or other pressure signs... Seems every load..( 300 BLK OUT...6.5 Gren...5.56 Ect).. I have used Win Primers with the past 6 months has been "HOT"...not in FPS but plenty pressure signs. Has anyone else had issues with Win Primers? Maybe try CCI, Rem or Fed ?? Rifle is a Marlin X7. I'm at 3700' Elevation. Rifle is grouping from 2" down to .75 (Faster the better)
Maybe bad Chrono ?? Showing wrong speed??? Thoughts Please
IMO .02 off the grooves sounds too close. my 7-08's preferred .010-.020 off lands and 120gr Nosler BT's
Also, Rem 9 1/2 primers proved best. I seem to remember some wicked pressure curves with some powders on the 7-08. Best powders I tested in order where Varget, VV n-540, IMR4350 and WW 760.
 

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