Pressure Signs Help Needed

[keithcandler]

Bush the firing pin in your bolt after you "blank" a primer. You will wait a long time till a primer "blanks" on LR.

I have my Rem and 40 x's with small bolt face, bushed, never a large bolt face or mag bolt face. Let the primers flow.

 

[longshot22-250]

Watch how much you crimp also . Don't over do it . Less is better.

 

[keithcandler]

No crimp is better.

I am NOT a fan of Nosler brass or Federal brass. I will not build a house on a sand bar in the middle of a river, also.

 

[ThrdKllr]

I've had the same problem with a batch of 4831 in my 7mmRM.

 

[jrsv2203]

Hi guys!

Pertinent info:
Rem 700 LH
280 AI
162 ELD-M .020 off lands
H4831

I need help reading pressure signs:

Case on bottom 56.8 grains 2770 fps which should be safe
Case on top 61.5 grains 3041 fps makes me nervous because the Nosler manual says 59.0 is max

Both have ejector marks, help me understand.

Start with new brass. Fire a round at book minimum load and measure the diameter of the case at the web of the case just in front of the extraction groove and at the head at the rim. Using the same lot of new brass, increment up until the same measurements increase.0005 inch. That is max in your rifle. At that point, the brass is beginning to flow (60,000 psi).

 

[jrsv2203]

Another pic:

Different lots of factory ammo I guess (different head stamps, but both are trophy grade 160 AB)

Both have been fired once as factory loaded ammo, left has just been tumbled, sized, wiped clean, and primed. Nothing has been done to the right.

Note: both have marks and swipes in 6 o'clock position

See my reply about case measurement comparisons. Up until you can measure a difference over a min load, you're still getting elastic deformation, e. G. The case expands and springs back. As soon as the measurements increase you are now getting plastic deformation which occurs very close to maximum pressure. More than that and you will start losing primers and sticky bolt. Way too hot!

 

[Indian7953]

Take a look at your once fired brass and see if you have an ejector mark on those. Those marks in your photos might have been there from the factory loading. Your primers are cratered but not flattened out very far. I think you're OK, check your once fired brass for Ejector marks.

 

[Wy Will]

I'd say you are just fine. Probably nearing max, but still safe. The book loads are more of a guideline than a requirement. Every load I have ever worked up for my 6.5-284 has been a fair amount above book max and I still have no pressure signs. Guys working up wildcat loads don't even have a book to go off of and work up until they see pressure signs and then back off. I generally stay below listed max, but I still only see it as a guideline.

 

[John Klingenberg]

I don't see those cases being strained. A lot of rifles do that to primers when it's not bushed. What I look for in a primer is when the outer edges loose their rounded edge. When they look squared off you got pressure.

 

[comen]

Brass originated as Nosler Trophy Grade 160 AB factory ammo fired through the subject rifle. This is the first time it has been reloaded. So it has been fired 2x. First time as factory, and this time.

If you have ejector marks on the case head, something is causing high pressure. "Any time you see a(sic) ejector mark on the base of the case it means the pressure was so great the brass flowed into the ejector hole. This means the brass stretched beyond its elastic limits for that brand of brass."(bigedp51 ) There could be factors other than Charge weight causing the over pressure, but it's there whether we like it or not

 

[Rflshootr]

Check your case length. If it's too long, trim it.

 

[ThrdKllr]

Make sure your chamber and brass are completely oil free. A little case lube in the chamber or on your brass will cause the ejector marks. Factory Remington 700's are bad about cratering primers. I had to have my 700P bolt bushed to stop it.

 

[Iron Worker]

I wouldn't bat an eye at those,in view of the fact that bolt lift was normal . BUT if the next primer you seat fits loosely than the head has expanded which is a solid clue .

 

[Mc Fraser]

Can you take a picture of your bolt face?