30-06 Pressure Signs

[ThirtyAughtChris]

Howdy Brothers,

I’ve had a curved grip Browning BLR chambered in 30-06 for about 25 years. I’ve experimented with it enough to think I know it well. I’m almost over confident with it. That’s why I’m slightly concerned. That gun has made some quite impressive groups over the years. It normally makes 5/8” groups at 100 yards with several different bullet/powder/primer/brass combinations. Its relationship with factory ammo is not so good, 1.5” usually. The only exception to that were the “light magnum 30-06” loads that were long ago discontinued by Hornady. It put those into 3/4”. I still have some of those. Anyway… I loaded up some Barnes LRX 175 grain with 55 grains of H4350, COAL 3.390 (about 10 thousandths from the lands in that gun) in R-P 3 times fired brass. The chrono avg of 3 rounds was 2813. 100+ fps quicker than expected. Slightly flattened primers (which didn’t concern me because every White River Primer I’ve used has been identical in every platform and round), no resistance on the lever, no extractor mark, no problems at all. All of the other guns and ammo shot across that chrono the same day were exactly where I expected them. It was 22°, 5000 ft elevation, 30% humidity. I thought I should investigate the situation so when I got home I disassembled 5 of those rounds, measured the powder charges on a freshly calibrated digital scale, and individually double checked them on a beam scale which agreed. Three were perfect, two were 2/10 grain over. It seems too good to be true. Any thoughts?

 

[JFK]

Guessing you picked up the extra fps from being close to the lands. Most of Barnes data assumes a good amount of jump in the .050-.100 range. Much closer than .020 off, and copper bullets can pressure out quickly if close to max charge. Run it if you like it, but be aware you are likely a little over pressure.

 

[Xxtavixx]

I dont know much about the BLR action, and how it handles the transition from slightly over pressure to just enough over pressure to be problemstic. That said, two major points need to made:

1: 22 degrees is cold, what do you think your pressure might be at 80?

2: no animal is going to care if its 100 fps faster, if safety is a concern it’s just not worth it.

You dont seem convinced your have over pressure. I dont have any experience with those primers, but slightly flattened primers are normally the first sign of over pressure

 

[ThirtyAughtChris]

Guessing you picked up the extra fps from being close to the lands. Most of Barnes data assumes a good amount of jump in the .050-.100 range. Much closer than .020 off, and copper bullets can pressure out quickly if close to max charge. Run it if you like it, but be aware you are likely a little over pressure.

That makes sense. I’m going to proceed with caution.

 

[ThirtyAughtChris]

I dont know much about the BLR action, and how it handles the transition from slightly over pressure to just enough over pressure to be problemstic. That said, two major points need to made:

1: 22 degrees is cold, what do you think your pressure might be at 80?

2: no animal is going to care if its 100 fps faster, if safety is a concern it’s just not worth it.

You dont seem convinced your have over pressure. I dont have any experience with those primers, but slightly flattened primers are normally the first sign of over pressure

1) I was thinking the same thing.

2) I’ve never been a velocity nut.

3) The three rounds I fired were on top of each other. I liked that.

I’m going to back the charge down a bit and compare them.

 

[OXN939]

I’m going to back the charge down a bit and compare them.

This is exactly what I'd do. Keep in mind that charges in factory ammo are generally measured by volume rather than weight, so the actual amount of powder routinely varies by half a grain or more.

That is to say, your .2 grains of variance isn't much in the grand scheme of things. And, if you backed your target charge weight off by half a grain to get into the territory of safe pressure, you would be unlikely to see any negative effects to any metric of that load.

 

[WV Mountaineer]

Howdy Brothers,

I’ve had a curved grip Browning BLR chambered in 30-06 for about 25 years. I’ve experimented with it enough to think I know it well. I’m almost over confident with it. That’s why I’m slightly concerned. That gun has made some quite impressive groups over the years. It normally makes 5/8” groups at 100 yards with several different bullet/powder/primer/brass combinations. Its relationship with factory ammo is not so good, 1.5” usually. The only exception to that were the “light magnum 30-06” loads that were long ago discontinued by Hornady. It put those into 3/4”. I still have some of those. Anyway… I loaded up some Barnes LRX 175 grain with 55 grains of H4350, COAL 3.390 (about 10 thousandths from the lands in that gun) in R-P 3 times fired brass. The chrono avg of 3 rounds was 2813. 100+ fps quicker than expected. Slightly flattened primers (which didn’t concern me because every White River Primer I’ve used has been identical in every platform and round), no resistance on the lever, no extractor mark, no problems at all. All of the other guns and ammo shot across that chrono the same day were exactly where I expected them. It was 22°, 5000 ft elevation, 30% humidity. I thought I should investigate the situation so when I got home I disassembled 5 of those rounds, measured the powder charges on a freshly calibrated digital scale, and individually double checked them on a beam scale which agreed. Three were perfect, two were 2/10 grain over. It seems too good to be true. Any thoughts?

Load and shoot it is my thoughts. The 30/06 is so poorly under loaded in factory offerings, it’s easy to start getting shy when you are loading it much faster then factory specs. If pressure signs aren’t there, then it s safe.

 

[ThirtyAughtChris]

1) I was thinking the same thing.

2) I’ve never been a velocity nut.

3) The three rounds I fired were on top of each other. I liked that.

I’m going to back the charge down a bit and compare them.

Also, the BLR action is stronger than many modern bolt actions. It is a rotating bolt with 6 locking lugs. I would never use that as a reason to think that exceeding normal pressure is acceptable. I was just letting you know. You should check one out if you get a chance. I love mine.