Do some rifles show pressure signs before others?

spenom

spenom

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Do some rifles show pressure signs before others? I hear of some guys running certain loads that I know would show pressure signs in my rifle. For example I know with a hornady 143 ELD-X loaded 0.02 off the lands my .260 Remington can run 46.5 grains of H4831sc before seeing pressure signs, 48 grains of h1000 before pressure signs, and 42.5 grains of H4350 before pressure signs with this load at zero degrees. I hear of lots of guys suggesting 43.5 grains of H4350 for this bullet. With my rifle that is going to show ejector marks and flattened primers. Also I am sure these same guys with these suggestions are out there in weather warmer than zero degrees so that would add to the pressure issue.

So with for example with 2 of the exact same rifle with the exact same loads shooting on the same day..... I think you get my point here. Basically is pressure or signs of it totally rifle specific all things considered equal? That said I am assuming there are some rifles that can't handle some higher pressures. Like when a guy reads about the 6.5X55 factory loads being weak because of early rifles chambered in this round that can't handle the higher pressures. Now to go further with that train of thought, are there certain rifles out there that are known for being able to handle higher pressure loads due to there design for example? If so what rifles are known for that? On the flip side what rifles have a reputation for early pressure signs? or am I a little bit off zero with my thinking on this topic?
 
All rifles show pressure signs at different max’s. I had two identical rifles in 223 bought 2 years apart that I had to work up two separate loads for. (Both rem 700 same model)
I recently rebarrelled a different rem 700 tactical and had to work up a new load. (Barrel manufacturer, length and twist changed so this was expected.) Everything from the rifle action, barrel twist and manufacturing process to your brass, primer, bullet and especially powder will affect your pressures.

I have a buddy that only buys powder in 8lbs jugs and sequential lot numbers for his peace of mind and consistency,whether it has any bearing on anything I don’t know but he gets good results.

I also have a 338 Lapua ackley that I had built to virtually the same specs as the builder with the same gunsmith and tools, and I still worked up a load starting at a 338 Lapua max and settled on one that is 1/2 a grain lighter than his.
Every gun should have a separate max, there are some safe loads that you will work up and feel good shooting in any rifle but don’t just go to max and call it done.
 
Powders do change lot to lot. One way I get around that if I can't find 8lber's is to mix 1lber's together in an empty 8lb container so variances even out. A chronograph , I find , is essential for really knowing what is going on with your reloading.
 
Rifles will absolutely take different maximum loads, or give different results with the same loads. That's why there are starting loads.

What are your velocities? I've got/had rifles that would match any manual's top velocity with the starting loads, although they couldn't keep up with the internet.

A tight chambered, well fitted rifle with neck or minimally sized cases might not show any pressure signs before an extractor mark or sticky bolt shows up. A sloppy one can show dinner plate sized primers with factory loads.
 
Pressure is pressure... 60,000PSI is 60,000PSI. how it shows on the fired brass varies alot as you have already seen.

tight or rough bores can effect how much effective pressure is caused by the same ammunition. ie same ammo shot in varying rifles can and will show varying chamber pressure.

how the action is built will affect the "pressure signs" you see on the brass. Poor fitting and out of alignment lock up will give more pressure signs like hard bolt lift, primer cratering, shiney case heads much sooner

So yes, it is possible to build rifles that can mask traditional pressure signs. A number of factory and custom actions have very tight lock up and better assembly tolerances so can mask pressure signs much better.

That does not negate that high pressure is still present.. no matter what the marketing suggests.

I personally think that new shooters and reloaders should use rifles that show pressure signs at the same time that load pressures approach SAAMI max. That gives them a clear and SAFE signal to stop. Maybe an ill fitted factory rifle is not such a bad idea?????

Chronographs can be very helpful here... no reloader is going to defy the laws of physics.. said another way... "no free lunch".

Leave the HERO reloading to the "experienced" reloaders... when things go south, at least they should have known better.

Jerry
 
The min load in the book for 30'06 of H380 with a 147gr fmj in my Bill Wiseman barrel and universal receiver has severely mashed primers and the velocity is quite a bit over the listed velocity for the max load.

That one stands out far more than any normal rifle I own and load for.


Dogleg said:
Rifles will absolutely take different maximum loads, or give different results with the same loads. That's why there are starting loads.

What are your velocities? I've got/had rifles that would match any manual's top velocity with the starting loads, although they couldn't keep up with the internet.

A tight chambered, well fitted rifle with neck or minimally sized cases might not show any pressure signs before an extractor mark or sticky bolt shows up. A sloppy one can show dinner plate sized primers with factory loads.
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