Look at the Difference in Brass Softness!

[atblis]

I've never experienced the sticky bolt lift thing. Is that really that good of an indicator of over pressure?

 

[25WSM]

On alot of custom actions no it's not. And if you get a hard bolt lift you are already way over pressure. When you see someone tapping their bolt handle with a mallet to get it open your at primer blow out stage.
Shep

 

[gjn11]

I shot identical loads in my 270 Weatherby using both Federal and Norma brass. Federal brass was consistently 80 fps faster than Norma brass so there was obviously a pressure difference between the two makes of brass. Experienced the same thing with 17 Remington using Nosler and Remington brass. Loads that were fine in Remington brass were to hot in Nosler brass.

 

[DUSTY NOGGIN]

come on man !!! we gotta keep the new guys from thinking this is ok to do , we got a lof new guys lately

whenever you change a component , you reduce and work back up until you see ANY pressure sign that includes ejector marks

OP , changed a component without working back up ,

 

[Edd]

I've never experienced the sticky bolt lift thing. Is that really that good of an indicator of over pressure?

I don't think it is a good indicator of the beginning of high pressure. I have had normal feeling bolt lift on loads so hot that they would puff smoke and gravity would make the primer fall out of the case.

 

[bigedp51]

Sticky bolt lift is also called primary extraction, meaning lifting the bolt straight up is to break the cartridge free of the chamber walls. Secondary extraction is being able to pull straight back on the bolt and eject the case.

In a semi-auto the resized case should be .003 to .005 smaller in diameter that its fired diameter. This allow the case to spring back from the chamber walls and extract reliably.

So sticky bolt lift could also be caused by not reducing the case diameter enough during full length resizing. But the general consensus is sticky bolt lift is caused by high pressure that also can vary with brass hardness.

In the 1968 Congressional hearings on the M16 rifles jamming problem, one of the problems was brass hardness. Meaning the brass was too soft and now Lake City has the hardest brass.

The photo below was posted at accurateshooter.com and this long range shooter said in increased the load until he got ejector marks. He then reduced the load knowing the elastic limits of the brass.

 

[ronstone09]

Identical load with different brass. 7mmRM 155gr at 3,260fps

Norma and Federal

I though nosler brass was made by norma ?

 

[okie man]

My pet load in 308 win using federal brass has zero signs of pressure but if I put the same charge in Remington brass it craters primers and starts showing ejector marks. The Remington cases also weigh about 10 grains more on average.

 

[KJW]

I've seen the exact same thing recently in a friends 300 RUM. Was trying to help him dial in his load and didn't know he has two different flavors of brass. Every so often we'd get a sticky bolt and super shiny ejector mark. I started diving into it and found he had Remington and Nosler brass and nosler brass was not taking the charge as well. No issues with the load in Remington brass. I use nosler brass on my 300 win and 338 LM. Both shoot exceptionally well but at lower speeds than most. Nothing wrong with it but this is a great thread to let guys know that brass is definitely not created equal

 

[Lefty7mmstw]

That load is about 150 fps too hot for anyones brass.

yup, unless it's a rather long barreled 7rem... a 24" barrel should run around 3100 fps with a 150... I don't know why people run the 7rem at 80Kpsi (instead of running a 28nos or 7stw) then wonder why they get shiners on normal brass.

 

[Scott E Ames]

Looks like both primers have pressure signs also (or the firing pin needs to be bushed). As has been stated here many times , when you get higher than published velocity figures it is likely because you are over pressure. We would all like to be the one with a really "fast" barrel. We are NOT. Don't be the person who puts their hand in the fire to see if all the warnings about heat are true.
That circle around the F on the federal case is a warning sign also.

 

[snox801]

I agree bolt lift is already way over pressure I look for swipe and primer mainly.
Cratering is not a great indicator because as stated may need a bushing. I have a 6.5 that always does it. But both show flattened primers which tells me it's already up in pressure.

 

[johnnyk]

"Edd said:

That load is about 150 fps too hot for anyones brass.

yup, unless it's a rather long barreled 7rem... a 24" barrel should run around 3100 fps with a 150... I don't know why people run the 7rem at 80Kpsi (instead of running a 28nos or 7stw) then wonder why they get shiners on normal brass."

I agree that OP's listed load is showing pressure signs and he should back down 1-2 grains of powder. A 24" barreled 7mag should "run around 3100 fps with a 150". Really?



Nosler doesn't stop at 3100 and neither do I.

 

[Ingwe]

yup, unless it's a rather long barreled 7rem... a 24" barrel should run around 3100 fps with a 150... I don't know why people run the 7rem at 80Kpsi (instead of running a 28nos or 7stw) then wonder why they get shiners on normal brass.

mines 26"