Pressure signs

[powdergun]

So I was looking at some brass and noticed some slight extractor marks which would indicate pressure issues. However, it was only on a certain brand of brass and even on some lesser loads.

It seems that only the federal brand brass showed signs and Hornady brass did not. The hottest load was within the amount given in the manual and not some silly amount. Of the four loads tested there was Hornady and federal brass used. Zero signs on the Hornady but the federal showed signs even at the lowest load.

All rounds ejected easily and were not hot.

Hottest load was 69gr or IMR 4831 behind a 185 gr Berger with Win mag primers(300 WM)

I have seen load books with up to 72gr for this weight bullet.

 

[B]

Federal's commercial brass stock is infamous for being soft. You are doing fine I would say.

 

[Eagleye]

Yep, Federal brass is notoriously soft when compared to most other makers offerings.
I have dumped all my Federal brass with the exception of 30-30, which is not a high
pressure chambering. Dave.

 

[AaronL]

I’ve also noticed this on some load workup for my .243 with a bunch of federal brass a buddy gave me. Weird thing was I started at minimum to maximum (37-40grain for 100 grain projectiles). I loaded 4 more in .5 grain increments above max recommended just to see if I could see pressure signs as I have never seen any on the Winchester brass I’ve always used. Had a slight extractor mark on the 40, but nothing on the 40.5, 41, 41.5, or 42. All rounds ejected easily.
Thought that was curious but with the pressure sign on the 40, decided not to load anymore above 39.5. Loaded 9 rounds in each .5 grain increment from 37-39.5, and upon testing all those 2 of both the 39 grain and 39.5 grain loads had slight extractor marks. Again all rounds ejected easily....
Thoughts? Seems like quite the variation in brass. Relatively new to reloading, but at about 16 reloads on my 60 pieces of Winchester brass I started out with. About 1000 rounds roughly. Have never seen any pressure signs on those...
The 39.5 grainers averaged 0.567” groups though....so quite pleased with that as the 100 grain projectiles are a bit heavy for the 9 1/8” twist

 

[Potashminer]

Has been posted here by Ganderite, several times, that true ejector mark (deformity on case head, brass is flowing) is not a sign of a little bit over pressure - it is a sign of a LOT overpressure - like proof load levels - north of 75 K psi. I go with whether the primers are still going in snug on 4th or 5th re-load - if so, load is okay, I believe - if they get loose before then, load is too hot, at least for that brass in that rifle. But my main "test" is the chronograph - do not remember how I would even go about working up a load, if I did not have one. No one says all brass the same hardness or alloy - from loading manual almost always report the brand of brass, the brand and model of primer, etc. that they tested with.

 

[Eagleye]

The 100 grain projectiles are a bit heavy for the 9 1/8” twist

I do not agree with this. I have been loading and shooting .243/6mm rifles for near 5 decades, and have never had a problem stabilizing
100 grain bullets in the 9-1/8" twist that Remington uses. Even the longer boattails are fine.

I also had 2 offshore 6mms, plus a M70 243. These had 10" twists and still gave no problems with 100 grain bullets. The original problem
was Remington's 244, which was twisted at 12", and usually [but not always] gave problems with the 100 grain spitzers.
That is why Nosler made a 100 grain Semi-spitzer in 6mm. Being shorter, it would stabilize in those 12 twist 244 rifles.

The bullets that need a quicker twist [ I use a 1-8"] are the Berger 105/108 grains, and the Lapua 105 Scenar, plus any 115 grain. Dave.

 

[MRP]

Remington's 244, which was twisted at 12", and usually [but not always] gave problems with the 100 grain spitzers.
That is why Nosler made a 100 grain Semi-spitzer in 6mm. Being shorter, it would stabilize in those 12 twist 244 rifles.

I remember back about 40 years now old Ziggy working on a .244, at least I'm 90% sure it was a 244. I remember talking about slow twists anyhow and he was showing me the before and after targets. He had slugged the barrel and found a tight spot and cut it there. Changed the holes from loose raged to tight clean cut group. Faster twist helps but the end all is at the end...some times.

 

[Buckmastr]

Federal is good brass but usually is heavier, with less fired internal volume compared to W-W or Rem, so runs a bit higher pressure with all else being equal.

 

[Ganderite]

The "book loads don't mean much. Their max load could be way too hot for your rifle. That is why the book has a START load.

Federal brass is soft. A slight ejector mark would not upset me IF the velocity is not over the book max velocity with an appropriate powder. You can't measure pressure, but you can measure a surrogate - velocity.