New Reloader Looking for Help on Fire Forming New Brass for 7mm-08

[Harvey_NW]

There aren’t problems if the person is well acquainted with how to use them.

I tried really hard to put that in a positive tone, even rewrote that sentence three times, but I can’t help saying if someone can’t figure it out they should use sloppy chambers.

I’ve burned up enough barrels with tight chambers without a single malfunction to not take people seriously that can’t figure it out. Heck, back in 1982 I can remember the article that was the turning point that warned hunting rifles are sure to jamb up if tight chambers or neck sized brass are used. It didn’t match my limited experiences and the half baked claims were a lot of bla bla bla, and 43 years later the same old arguments are used and broadcast as gospel.

It’s not an exaggeration that I’ve never had as much as a really heavy bolt lift. Clickers while developing loads prior to finding a reasonable max, but never a failure to chamber or extract, let alone carbon rings or such silliness from a lack of effort.

I’m not saying they are for everyone - obviously many folks struggle and get frustrated when peeing into the wind doesn’t work out. Today’s marketing power houses don’t help when the number of products, cartridges and ideas sold to shooters are more to separate folks from their money rather than contribute to reliability, and they have convinced people to blindly trust and not really understand what they are buying into.

I guess if that's what you're into, cool. But I've had minimum chambers that show pressure early, produce clickers, then require some sort of collet body sizing die, and if you get a spec of dirt on the case they close tightly, and blah blah blah. Dumb. Zero reason for tight chamber dimensions. The best shooters in the world full length size brass with .002" shoulder bump for a reason. You do you.

That sounds like terrible luck.

It's not luck, it's a volume/pressure relationship. If you load near pressure with new brass, you will almost always have to adjust your charge to get out of pressure on fireformed brass. If you load conservatively, you'll probably never notice any difference.

 

[TaperPin]

The best shooters in the world full length size brass with .002" shoulder bump for a reason.

It’s not your fault, you’ve been conditioned to accept the half baked ideas. It’s like running a race car, the extra performance requires more attention than driving a pickup truck. Shoulder bump is used by all the shooters in accuracy sports. Literally every accuracy record is set with a minimum dimension chamber and shoulder setback for easy chambering that doesn’t disrupt how the rifle is sitting in the bags. During good conditions benchrest or F class matches go rapid fire.

What usually causes problems are mismatches between the chamber and dies. The average shooter doesn’t even know how to identify how the case interacts with their chamber, let along transfer that to how the sizing die is working the case, let alone knowing the shape of the chamber. It’s mysterious if someone doesn’t understand it.

 

[N2TRKYS]

That sounds like terrible

It's not luck, it's a volume/pressure relationship. If you load near pressure with new brass, you will almost always have to adjust your charge to get out of pressure on fireformed brass. If you load conservatively, you'll probably never notice any difference.

I always load at or alittle above book max and have never had to adjust a load from virgin brass. I hate that y’all have had the run of luck that y’all have had. Or maybe it’s your sizing technique.

 

[Notorious BEN]

So for my 3 sources I have the following for a 140gr jacketed bullet and N150:
1) 38.5-42.5
2) 37-41
3) 39.4-42.2

I plan to start with 39.5gr of N150 and see what those 3-5 shots get me before I go any further.

I arrived at that charge as being safe because it's 1.5gr lower than the lowest max charge weight from source 2 and just 0.1gr higher than the starting load for source 3. It's 1gr higher than the starting charge, but still 3gr lower than the listed max for source 1.

Please advise if I'd be better off going with something lower.

Once again I do not have anyone locally to advise and I want to avoid blowing up my rifle and injuring myself and others.

 

[wind gypsy]

So for my 3 sources I have the following for a 140gr jacketed bullet and N150:
1) 38.5-42.5
2) 37-41
3) 39.4-42.2

I plan to start with 39.5gr of N150 and see what those 3-5 shots get me before I go any further.

I arrived at that charge as being safe because it's 1.5gr lower than the lowest max charge weight from source 2 and just 0.1gr higher than the starting load for source 3. It's 1gr higher than the starting charge, but still 3gr lower than the listed max for source 1.

Please advise if I'd be better off going with something lower.

Once again I do not have anyone locally to advise and I want to avoid blowing up my rifle and injuring myself and others.

What brass are you using?

I'd probably load 40.5-41 grains if you were using pretty typical capacity brass.

Really what i'd do is do 39.5-43 grains in 0.5 grain increments just looking at velocity and pressure signs but understand not everyone wants to take extra range trips to do that.

 

[Dan Carey]

Don't worry about blowing up your rifle. The brass case is the weak link. Look at the primers for excess flatting, Don't over think this process, its not that difficult unless you make so. When the primer falls out of the case or you see smoke coming from the action, you are over max. Other than that you are just overworking the cases with hot loads. Start a couple grains below max and go from there.

 

[Notorious BEN]

What brass are you using?

I'd probably load 40.5-41 grains if you were using pretty typical capacity brass.

Really what i'd do is do 39.5-43 grains in 0.5 grain increments just looking at velocity and pressure signs but understand not everyone wants to take extra range trips to do that.

It's Starline so reputable brass.

I just want to start low and work up, but I'd like to do 3 shots just to look at average velocity for a given charge.

I also realize you can do that with single shots too so I may load up 3 with 39.5, 40, and 40.5 for the first ones.

I'm going to take my time but there's not a lot of data out there for N150 and I'd rather not spend the $80+ on a pound of IMR 4350 from a local reloading supplier.

 

[wind gypsy]

It's Starline so reputable brass.

Not from personal experience but wouldn't be surprised if its a little lower in capacity than alpha/lapua/hornady/RP so more cautious starting charges isn't a bad idea.

I just want to start low and work up, but I'd like to do 3 shots just to look at average velocity for a given charge.

You can get pretty dang close by plotting out speed from a 1 charge ladder by and smoothing out the curve from shot to shot. The "flat spots" and "spikes" will go away with larger shot counts.

 

[Harvey_NW]

It’s not your fault, you’ve been conditioned to accept the half baked ideas. It’s like running a race car, the extra performance requires more attention than driving a pickup truck.

What usually causes problems are mismatches between the chamber and dies. The average shooter doesn’t even know how to identify how the case interacts with their chamber, let along transfer that to how the sizing die is working the case, let alone knowing the shape of the chamber. It’s mysterious if someone doesn’t understand it.

Half baked ideas, lol. There is a point of diminishing return. When you can take a decent quality factory rifle and use a $55 die set to work up a load that shoots .6" 10 shot groups, you tell me where the performance potential is. Most of the voodoo node and tuning believers on here still won't shoot sufficient groups to prove anything, ever. Why do you think one of the best competition rifle builders known to the sport developed his own reamer with larger specs than the SAAMI ones? Does PRCW ring a bell? It's mysterious if it doesn't..

I always load at or alittle above book max and have never had to adjust a load from virgin brass. I hate that y’all have had the run of luck that y’all have had. Or maybe it’s your sizing technique.

Awesome, I didn't say book max, I said pressure. As in sticky extraction, ejector marks/swipe, flattened/cratered primers, excessive velocity. There is a difference, and I will bet that if you work up to just under pressure on new brass, it will have signs on fireformed and FL sized brass with -.002" shoulder bump if you use the same charge.

 

[TaperPin]

Half baked ideas, lol. There is a point of diminishing return. When you can take a decent quality factory rifle and use a $55 die set to work up a load that shoots .6" 10 shot groups, you tell me where the performance potential is. Most of the voodoo node and tuning believers on here still won't shoot sufficient groups to prove anything, ever. Why do you think one of the best competition rifle builders known to the sport developed his own reamer with larger specs than the SAAMI ones? Does PRCW ring a bell? It's mysterious if it doesn't..


Awesome, I didn't say book max, I said pressure. As in sticky extraction, ejector marks/swipe, flattened/cratered primers, excessive velocity. There is a difference, and I will bet that if you work up to just under pressure on new brass, it will have signs on fireformed and FL sized brass with -.002" shoulder bump if you use the same charge.

I agree most shooters don’t need or want anything fancy.

I won’t argue against Alex Wheeler’s reamer designs - for anyone reading this that doesn’t know, Alex added a little extra taper to the sides of PRC chambers so brass extracts more reliably without clickers, something Hornady should have done from the beginning.

Hornady has single handedly done the most to cause problems by marketing poorly thought out cartridge designs, but the PRC line is about as tapered as Ackley Improved cartridges are and they share the same issues. Back in the 1980s when writers were complaining about minimum chambers in the custom guns that were having problems, take a guess what the popular cartridges were - everyone cool wanted an AI. With .008” per inch of taper they are on the edge of having problems reguardless if the chamber if minimum or sloppy, the side angle is the problem. Poor cartridge choice then or now is the problem. The best way to prevent clickers in a 280ai is to get a 7 Rem mag with .012” per inch of side taper, or a short mag of your favorite flavor, or alter the sides of the chamber. Same solution for the 7 PRC, just don’t buy one, or know it has to be fixed. Heck even RUM, SAUM, Winchester Short Mag, etc have more like .012” per inch of taper and how often do we talk about their clickers?

Yet everyone flocks to Hornady eagerly asking for another.

 

[Dan Carey]

"I will bet that if you work up to just under pressure on new brass, it will have signs on fireformed and FL sized brass with -.002" shoulder bump if you use the same charge."

Would you explain this to me in detail?

 

[N2TRKYS]

Awesome, I didn't say book max, I said pressure. As in sticky extraction, ejector marks/swipe, flattened/cratered primers, excessive velocity. There is a difference, and I will bet that if you work up to just under pressure on new brass, it will have signs on fireformed and FL sized brass with -.002" shoulder bump if you use the same charge.

Then you would be wrong, cause I have never had that happen with my loads. I walk mine up to pressure, but when backed off they hover within a grain or so of book max for me. So, again, maybe it’s something in your technique that’s giving you issues.

Good luck getting it figured out, cause it sounds like a pain having to tweak your loads like that.

 

[HandgunHTR]

Then you would be wrong, cause I have never had that happen with my loads. I walk mine up to pressure, but when backed off they hover within a grain or so of book max for me. So, again, maybe it’s something in your technique that’s giving you issues.

Good luck getting it figured out, cause it sounds like a pain having to tweak your loads like that.

I have had it happen on a couple of standard cartridges. A 308 using LC brass was probably the most notorious for me. It was a Savage Model 10 FCP. This was back when I wasn't as educated as I am now. I worked up a load using virgin brass. It was near (but not at) book max. Little did I know that "book max" and "firearm max" can be wildly different. Fast forward to me loading up 200 rounds of this wonderful load only to end up having sticky extraction, pretty significant ejector swipes, and super flat primers with the first couple that I fired.

Come to find out that the shoulder on the fired brass was, on average, about 0.007" farther forward than on virgin brass. Therefore the necks were farther forward too. I was only neck-sizing at the time as well.
When you load has the bullets seated 0.010" off the lands and you don't actually measure the COAL or CBTO length because you set your dies using virgin brass, you now have bullets that are only 0.003" off the lands. As most experienced reloaders know, the variation between bullets can be that much, depending on the bullet. So, you can see where this is going.

All that being said, it can happen. Some cartridges are more susceptible to it than others, but to claim that it happens "all the time" or "never" just means that your sample size isn't large enough.

 

[N2TRKYS]

I have had it happen on a couple of standard cartridges. A 308 using LC brass was probably the most notorious for me. It was a Savage Model 10 FCP. This was back when I wasn't as educated as I am now. I worked up a load using virgin brass. It was near (but not at) book max. Little did I know that "book max" and "firearm max" can be wildly different. Fast forward to me loading up 200 rounds of this wonderful load only to end up having sticky extraction, pretty significant ejector swipes, and super flat primers with the first couple that I fired.

Come to find out that the shoulder on the fired brass was, on average, about 0.007" farther forward than on virgin brass. Therefore the necks were farther forward too. I was only neck-sizing at the time as well.
When you load has the bullets seated 0.010" off the lands and you don't actually measure the COAL or CBTO length because you set your dies using virgin brass, you now have bullets that are only 0.003" off the lands. As most experienced reloaders know, the variation between bullets can be that much, depending on the bullet. So, you can see where this is going.

All that being said, it can happen. Some cartridges are more susceptible to it than others, but to claim that it happens "all the time" or "never" just means that your sample size isn't large enough.

Yeah, I’ve never seen the point of neck sizing, so I never bought into that hype. Seems like that one bit you.

Chasing the lands never made much sense to me either, so I never did that.

This reads like it was more about your technique that you bought into. Glad you got it figured out.

My sample size maybe too small. I only load for over a dozen rifles with 2 or 3 different loads for each rifle. Maybe I’ll change my technique one day and it’ll happen to me. Who knows?

 

[Harvey_NW]

"I will bet that if you work up to just under pressure on new brass, it will have signs on fireformed and FL sized brass with -.002" shoulder bump if you use the same charge."

Would you explain this to me in detail?

It's a volume/pressure relationship. It is theorized that some of the energy is consumed by expanding the new brass out to the chamber walls on the first firing. After brass is formed and bumped minimally, it takes less energy to expand the case, increasing pressure.

 

[Harvey_NW]

Then you would be wrong, cause I have never had that happen with my loads. I walk mine up to pressure, but when backed off they hover within a grain or so of book max for me. So, again, maybe it’s something in your technique that’s giving you issues.

Good luck getting it figured out, cause it sounds like a pain having to tweak your loads like that.

Well it's proven very repeatable for me in multiple calibers and component combos, so I know what to expect if I go about it that way. It's actually super simple, I drop the charge a bit.

 

[Dan Carey]

I guess the next question would be, are the reloading manuals using data from both new and well used brass and what kind of resizing dies do they use and are all resizing dies made to the same tolerances.
There must be a hundred minute factors affecting this pressure question. Virgin brass made by who? Does all virgin brass have the same volume? resized by what means?

 

[N2TRKYS]

Well it's proven very repeatable for me in multiple calibers and component combos, so I know what to expect if I go about it that way. It's actually super simple, I drop the charge a bit.

Glad you’re happy with it. I would hate to know that I had to tweak loads like that, though.

 

[Kimber7man]

Really what i'd do is do 39.5-43 grains in 0.5 grain increments just looking at velocity and pressure signs but understand not everyone wants to take extra range trips to do that.

Same here. Grand total of 8 rounds. Chart velocity of each and find your happy place.

 

[Harvey_NW]

There must be a hundred minute factors affecting this pressure question.

There is, which is why it's best to keep it simple and test for yourself in your rifle, with your tools, to see what works best for your unique combination.