Pressure Signs ?

[Webster]

I’m going to back it down to 68 grns of H4831 and use that for the maximum. 66.8 grns is listed on the Quick Load print out I have for 60K PSI. 70 grns just breaks the 3000 fps barrier on my chrono. I’ve got some 7828 I’m gonna try next. I’m just confused about the ejector marks vs the appearance of the primers.
The Quick Load print out shows 66.8 grns at 3044 fps (near max) and I never got mine that high. 67 grns barely makes 2900 fps in mine.

At work we had a statistics dept. to design and analyze experiments. It's difficult to account for cause and effect for 5 variables let alone 15+ in Quick Load. Your about 6 grs over max in reloading manuals even through your getting 3000 fps which matches manuals with much less powder. I don't trust QL I always go by manuals and not some computer questimate with a huge number of variables. Of course manuals may be a little conservative we don't know how they determine the max cut off point. The only thing that can sqeeze the case head into ejector hole is pressure.

You are at 66.8 t0 70.0 grains!!!

Per my Sierra reload manual:
154 gr bullet with 4831 has 61.9 grs max load at 3000 fps.
160 gr bullet with 4831 SC 63.6 grs max load at 3000 fps.
Berger manual:
140 gr bullet 62.0 gr max load with 4831 at 3086 fps.
168 Gr bullet 59.4 grs max load at 2887 fps

 

[OLEJOE]

My Sierra data is a little higher.

 

[Webster]

View attachment 1085912 My Sierra data is a little higher.

I have the Sierra 5th Edition manual copy right 2003. It's a lot different than your edition??? Bottom line you have signs of pressure.

 

[243winxb]

ADI makes AR 2213 sc for Hodgdon, known in the USA as H4831sc.

ADI has their own loading data for the 7mm Rem Mag.

The bullet type and its bearing surfaces has an effect on pressure.

ADI data.



http://www.adi-powders.com.au/rifle/

Hodgdon seems to use ADI data.

 

[OLEJOE]

This is not the first time I’ve had problems with this particular lot of powder. I had a 6.5x284 I loaded for and ran into pressure signs before I ever got up to max published loads and velocity was slower also. I sold the barrel, and new Lapua brass and the guy I sold it to told me he was using a good bit more of the same powder and getting a substantial more velocity out of it. I got better velocity and lower pressure with IMR 4350 in the 7 mag. I’ve got a can of IMR 7828 I’m going to try next and see how it goes. I’m not a speed freak but if I’m going to feed a race horse, I expect him to be able to run.

 

[FatBuddah]

There must be something to explain other then charge pressures causing these marks. I have a 7/300 Norma improved
37* shoulder bore rider throat set for 195g Berger EOL. I shot both Norma and Peterson 300 Norma brass - both fire formed cream of wheat and at the lans w/ reduced charge prior to full charge loads. Each time both ways i will get the marks. I have used a an assortment of powders from IMR 7828 SSC, H4350, RL33, VV570, & H50. After fire form I started with 33, as its my go to on the bigger calibers, and ran a ladder test starting at 77g on up (i even went as high as 95g) and every firing every powder every charge gives extractor mark.
Totally confused

 

[OLEJOE]

I was confused as well about mine. Even low starting loads left the marks. I have some different brass that doesn’t have any marks on it and it has been fired 3 times. Once factory ammo and reloaded twice. I agree with everyone who said I had high pressure with the top loading but it did it with the lower level loads. What did your primers look like? Mine were still as round on the edges as they were in the box. Maybe it has to do with the bolt face?
I backed mine down and I’m going to start over. That 7/300 should be a screamer.

 

[FatBuddah]

Primers looked as primers should as one climbs the charge ladder.... as loads got hotter primers reacted as they should. at the point of heavier than norm bolt lift, primers began to flatten. as far as this round being a screamer.... thats what i intended. I had a 7/300 win 26" tube that pushed the Berger 180's (RL-33) at 3250fps confirmed w/ radar and magneto and was an absolute takedriver. I thought hey.... heres an opportunity to maybe get better brass (Peterson and eventually Lapua) and shoot a bit bigger bullet. I figured it would at least match up to what i already had. So far speeds are not impressive and even though these marks may or may not deal with pressure, it sits in my head something is wrong and thats not good from behind the trigger. Setup is Defiance/Proof/Terminator T3

 

[OLEJOE]

I never got heavy bolt lift with mine. There is no swipe on it at all. Just the slight mark where the ejector hole is in the bolt face. But I read in another thread about chrono discrepancies and that may be some of my problems. But it doesn't explain why 1 powder would give acceptable velocities and another slower powder would not without excessive pressure. I don't have access to another chrono to check mine out so I guess I'll just have to live with it. Like I said, the loads with IMR 4350 were right by the loading manuals and the H4831 loads were not even close.

 

[Uncle Ed]

I’m just confused about the ejector marks vs the appearance of the primers.

If I read your posting correctly you are only getting ejector marks on your Winchester brass. This tells me the Winchester brass is softer in the base than the other brands.

The photo below was posted here and the poster stated he increased the load until he got ejector marks and then backed off 1 or 2 grains of powder. Meaning he was testing the strength and hardness of his cases to know their limits.

Brass flow into the ejector means you are pushing the brass beyond its elastic limits. And your problem is your primer cups are harder than your Winchester cases.

You could check the case capacity of the brands of cases you have and I bet the Winchester cases have the most capacity. And if they do have more capacity then brass hardness is the problem.

After Winchester lost the contract to produce ammunition at Lake City they sold off their brass manufacturing plant and now buy brass from the cheapest bidders to make their cases.

 

[OLEJOE]

I’ve heard that about Winchester before but they are one of the few manufacturers that have it available. I’ve got a lot of time spent on reforming these cases and I’m going to see how long the primer pockets hold up but I’m going to get some different brass and see how it works. I really appreciate all the help and suggestions. My ejector marks were not near as bad as the one you posted. Thanks again

 

[Bart B.]

Has anyone taken brass thought to be too soft to a shop to have it tested?

 

[Uncle Ed]

Has any6ever taken brass thought to be too soft tonal shop to have it tested?

Yes, our government did during the 1968 Congressional hearings on the M16 rifle jamming problem. One of the jamming problems was the 5.56 cases were too soft.

How Hard is Your Brass? 5.56 and .223 Rem Base Hardness Tests
http://bulletin.accurateshooter.com...r-brass-5-56-and-223-rem-base-hardness-tests/

Below Lake City and commercial contract 5.56 and 7.62 brass must meet military hardness standards.

Meaning Lake City brass is made Ford Truck Tough and is harder and tougher than Lapua brass.

In closing if the OP had read more Jack O'Connor stories he would not have had his problem with his 7mm Rem Mag.

That's because .270 Winchester owners know that the .270 Win is the worlds best non-belted magnum.

 

[Bart B.]

Yes, our government did during the 1968 Congressional hearings on the M16 rifle jamming problem. One of the jamming problems was the 5.56 cases were too soft.

Thanks for that info; 'twas new to me.

That must be why the USN shop building a dozen or so of the first match grade M16 rifles in early 1971, said the Remington .223 cases they sent to the USN Rifle Team at Annapolis Naval Station to handload Sierra 52 gr. Match bullets were verified hard enough. I think the Army and Marine Corps teams also used Remington cases. None of these teams had problems with their handloads at the 1971 Nationals.

 

[Bart B.]

In closing if the OP had read more Jack O'Connor stories he would not have had his problem with his 7mm Rem Mag.

That's because .270 Winchester owners know that the .270 Win is the worlds best non-belted magnum.

I didn't know the 270 Win was a non-belted (rimless) magnum, owned one for years.

Why are 27 caliber bullets in resized 30-06 cases better than modern rimless bottleneck magnums of any caliber at 65,000 psi?

This inquiring mind wants to know.

 

[243winxb]

Pressure signs for firearms.

 

[Uncle Ed]

I didn't know the 270 Win was a non-belted (rimless) magnum, owned one for years.

Why are 27 caliber bullets in resized 30-06 cases better than modern rimless bottleneck magnums of any caliber at 65,000 psi?

This inquiring mind wants to know.

At work two of my friends had 7mm magnums and several of us had .270 Winchesters and we argued endlessly on which caliber was best with the least bullet drop. And my posting was warped dry humor about belted case that were developed by the British in the early 1900s.

Then one day at work I brought in a article about loading a 30-06 to the same pressures as the .270 Winchester in a modern rifle like the Remington 700. And the belted caliber wars started anew and our supervisors were always telling us to police up our brass and get to work. And the funny part is the average deer in Pennsyltucky is shot at 40 yards and all you need is a 30-30 Winchester.

 

[Bart B.]

Why does SAAMI spec the 270 Win average peak pressure 5,000 psi higher and the 25-06 3,000 psi higher, than the 30-06 at 60,000 psi?

 

[Uncle Ed]

Why does SAAMI spec the 270 Win average peak pressure 5,000 psi higher and the 25-06 3,000 psi higher, than the 30-06 at 60,000 psi?

The SAAMI restricts the factory chamber pressure to the oldest and weakest action it will be fired in.

And if the 30-06 was loaded to the same pressure as the .270 at 65,000 psi it would be a real shaker and mover.

 

[OLEJOE]

The SAAMI restricts the factory chamber pressure to the oldest and weakest action it will be fired in.

And if the 30-06 was loaded to the same pressure as the .270 at 65,000 psi it would be a real shaker and mover.

‘03 Springfields.