Flattened Primers...

[therichardpowell]

So I just started reloading, and went out this morning to test out some loads and try to find my max load. I guess I will list out the components I am using and the processes I used to load them.

Stock Stevens 200 308 Win.

Winchester once fired brass
CCI 250 Primer, only primers I could find and my friend checked his Speer book and they called for a magnum primer for 2520
Accurate 2520 powder
Sierra 165 Grain Game King Soft Point Boat Tail
Neck tension on the ones I measured appeared to be .002"

Full length resized and deprimed using Hornady spray lube
Trimmed to 2.006", Chamferred and deburred
Tumbled in crushed walnut and nu polish and a touch of mineral spirits
Charged to exact by hand with a scale and a trickler
Bullets seated to .020" off the lands, No crimp

So I went and shot some this morning and got flattening primers way before I expected. I am using the Lee 2nd edition book, and they show a minimum load of 42.9 grains and a max of 47.7, so I started at 43 and increased in .5 grain increments. 43 grains shows no primer deformation, 43.5 I could tell the primer changed a bit but just barely, and 44 grains I got a flattened out primer...

43 Grains

43.5 Grains, Inconsistent flattening

44 Grains, flat...

I don't have any ejector indenting or stiff bolt lift, the only other thing I can see is a mark where the ejector appears to scrape on the head maybe when lifting the bolt? Picture #3 kinda shows it. Is this something I need to watch for as well?

So at what point do you start backing off? I felt like the 43.5 grain is probably the max. It just seems weird that I am getting pressure signs a half grain above minimum. I will probably load up 10 rounds each of some lower charges to try for accuracy but then I will be under the book minimum... I have since found some CCI 200 primers, should I try them and see how it goes? Just looking for ideas, again I am totally new to this so I just want to make sure I am being safe and gonna get the best BANG for my efforts. Thanks in advance for your guys' consideration.

Edit, I did do a search and found alot of bickering back and forth about things that are far beyond my realm of understanding at this point in the game. I am just looking to find out what you guys would do. Keep going? Stop there and shoot some groups? Switch powders and start over?

 

[Lefty7mmstw]

Well, from what my accurate data from 2005 says you are at the top charge at 44 grains roughly. For a 308 win with a 168 and 2520 and a cci200 they start at 40.5 and land at a top of 45.0. Kick it down a grain or so for a mag. primer and 44 it is. BTW. they are using the sierra 168 match at 2.800" oal.

 

[MudRunner2005]

I run 44.0gr of Varget in my .308 with 168 & 175gr bullets. No flattened primers.

I had my first flattened primers today at the range. Apparantly my new 7mm STW load for the Berger 180 VLD's is a little bit too hot. Primers are pancaking and the bolt is sticking and won't slide back. Guess I need to back it down a grain or so.

My primers are flattening on my STW 168 VLD load, but nowhere near as bad, and the bolt is not sticky, and it's shooting 1/2 MOA 3-shot groups. Guess I'll keep that load.

 

[Lefty7mmstw]

Edit, I did do a search and found alot of bickering back and forth about things that are far beyond my realm of understanding at this point in the game. I am just looking to find out what you guys would do. Keep going? Stop there and shoot some groups? Switch powders and start over?

When it really comes down to it it doesn't mean squat what the pressure is if she won't shoot well. Safety is **** important but she's gotta shoot too.
As far as the little things done to seating or brass to tweak a load, most factory pipes can't tell the difference. I don't personally do a **** thing that doesn't substantively add to the accuracy capability of my ammo. Whittling on your brass can add a lot of time and gets a lot less benefit that simply sizing, trimming, and cleaning/ inspecting your brass. Finding a bullet and powder your barrel likes will make all the difference.

What is your load shooting like at present?? Is there any hope of accuracy??

 

[Lefty7mmstw]

I run 44.0gr of Varget in my .308 with 168 & 175gr bullets. No flattened primers.

I had my first flattened primers today at the range. Apparantly my new 7mm STW load for the Berger 180 VLD's is a little bit too hot. Primers are pancaking and the bolt is sticking and won't slide back. Guess I need to back it down a grain or so.

My primers are flattening on my STW 168 VLD load, but nowhere near as bad, and the bolt is not sticky, and it's shooting 1/2 MOA 3-shot groups. Guess I'll keep that load.

Muddy, I think you've gotta step back a bit more than that on your 7stw if she's sticky. Here's a pressure graph you've seen before from my old sendero 7stw; the win 150 grain load hit over 70 Kpsi peak and she didn't have heavy bolt lift. I'd go 3 to 5 percent down on charge as your pressure should fall twice as fast as the charge drop.

 

[therichardpowell]

Well, from what my accurate data from 2005 says you are at the top charge at 44 grains roughly. For a 308 win with a 168 and 2520 and a cci200 they start at 40.5 and land at a top of 45.0. Kick it down a grain or so for a mag. primer and 44 it is. BTW. they are using the sierra 168 match at 2.800" oal.

That is good info, thanks. I checked their load data online and it is copied and pasted right out of my Lee manual, not very helpful...

 

[therichardpowell]

What is your load shooting like at present?? Is there any hope of accuracy??

Well, I set out with great intentions this morning... Got my table and targets and ammo and I get to the gravel pit and... No stool... I forgot my dang stool... So I shot just to check for pressure signs and then we packed it up and moved out to 500 yards for some feel good shooting off the hood of the truck. I shot some 150 grain Core Lokts with 46 grains of AA4064 in PMC brass. No development, just threw em together for the heck of it and zeroed my gun for them a while back. We were shooting across a big draw. 5mph winds where we were standing and I would figure about 10-15 out in the draw. After we figured out the wind we were hitting withing 6 inches of a clay pigeon in the gravel pit. They would have been viable kill shots, and we were just messing around. I wouldn't shoot that far at an animal with that wind... Not yet at least.

SO... Needless to say I will have to go back out next weekend and see if this ammo will group at all. And on a recommendation from another forum I am going to work up some 4064 loads to try out as well.

 

[MudRunner2005]

Muddy, I think you've gotta step back a bit more than that on your 7stw if she's sticky. Here's a pressure graph you've seen before from my old sendero 7stw; the win 150 grain load hit over 70 Kpsi peak and she didn't have heavy bolt lift. I'd go 3 to 5 percent down on charge as your pressure should fall twice as fast as the charge drop.

How does one go about measuring chamber pressure? I have always wondered that...All these guys know how much kpsi their loads produce, but I guess I have no idea how they measure that stuff.

I was reading on another thread, and a guy was having the sticky bolt issue with a 300 WM, sounded alot like mine, but he fixed his very quickly and simply, just by backing off the lands a couple thou. He said the bullet on the lands was causing some funky excess pressure spikes and causing his bolt to stick. He said he backed them off a couple thousandths, had his chamber polished, and now he has no issues at all. I guess I'll try his fix to see if it doesn't fix it first. Then I might have to get my chamber polished by my smith. Since it keeps leaving rough drag marks about 1/8" above the belt, even on brass on its second load...Which shouldn't be happening. Obviously I need to have my smith scope the bore anyway. Just want to make sure the throats still in great shape. Should be, since I should only be about 1/2 way theough my barrel's lifespan.

Found out the new (to me) 700 .338 WinMag won't hit the broad side of a barn. Cold-bore, shoots great. Second shot, close. Third shot, God's knows if it's gonna shoot high, low, left, or right, or any combo of those...

Looks like a good candidate for another 7STW...Being it's a Magnum LA receiver.

OR, I'm gonna make it a lightweight .257 Wby Mag for whitetail hunting. Haven't decided...

 

[Lefty7mmstw]

How does one go about measuring chamber pressure? I have always wondered that...All these guys know how much kpsi their loads produce, but I guess I have no idea how they measure that stuff.

I was reading on another thread, and a guy was having the sticky bolt issue with a 300 WM, sounded alot like mine, but he fixed his very quickly and simply, just by backing off the lands a couple thou. He said the bullet on the lands was causing some funky excess pressure spikes and causing his bolt to stick. He said he backed them off a couple thousandths, had his chamber polished, and now he has no issues at all. I guess I'll try his fix to see if it doesn't fix it first. Then I might have to get my chamber polished by my smith. Since it keeps leaving rough drag marks about 1/8" above the belt, even on brass on its second load...Which shouldn't be happening. Obviously I need to have my smith scope the bore anyway. Just want to make sure the throats still in great shape. Should be, since I should only be about 1/2 way theough my barrel's lifespan.

Found out the new (to me) 700 .338 WinMag won't hit the broad side of a barn. Cold-bore, shoots great. Second shot, close. Third shot, God's knows if it's gonna shoot high, low, left, or right, or any combo of those...

Looks like a good candidate for another 7STW...Being it's a Magnum LA receiver.

OR, I'm gonna make it a lightweight .257 Wby Mag for whitetail hunting. Haven't decided...

The easiest way to measure pressure is to get a strain gauge system. The one we were using the gauge was simply glued to the outside of the chamber and measurements were taken for steel thickness, etc.. You should get within a couple of thousand psi. of actual with one of these if you are careful. The only other way I know of is with pressure barrels with chambers side drilled to accept a pressure gauge. Not very portable; mainly for lab use.

The biggest thing people forget about when seating out to the rifling is the bullet won't have a run at the rifling and may essentially "stall" as it hits the rifling, causing the pressure to go up to overcome the drag. This is more trouble with mono. type bullets but can happen with others too. I let 'em run a bit if I can.