Hey all-

I have a question about changing from LC brass to Federal GMM brass on a load that my rifle shoots really well.

When I spent an afternoon with an experienced reloader, he held my hand while I loaded up a batch of his favorite load to shoot in my rifle. He was right. My rifle shot it into a tiny group so I would like to keep working with it.
My issue is this:
The load was in his Lake City brass. Mostly all I have is Federal Gold Medal, fired once in this rifle.

Do I do the standard "reduce by 10% when changing any component" here? Do I keep the same COAL of 2.806? All other components would be the same.
I know what the lawyers say. I'm asking about your own practices. I'm not publishing the entire load recipe here so maybe people will be less shy, liability wise.

Thanks!

Bruce

Just my $0.02.....

If you can get some LC Brass stick with it.

FGMM brass tends to be soft and won't last but 2-3 reloadings or less (if the load is hot). Primer pockets tend to give up/out quickly in my experience.

Getting a quality robust brass will ensure a longer life. Lapua or LC or Black Hills would all be good choices.

Andrew

The Federal is what I have available. The load is hot so I don't expect the brass to be good forever. I really just want to work the kinks out of my process before I go to the small quantity of Lapua I have stashed. I don't have more than 30 Lake City so they're not much help.

Bruce

If it were me, I'd keep the same COAL as that may be significant in the accuracy of your load (distance from lands).

If the load was maximum, I'd back down a couple of grains and shoot 5 or so and check for pressure signs. If there weren't any, I'd go up to where I was originally.

If it wasn't max, I'd load it just the way it was in the LC brass.

It was hot. I had to pop the bolt handle with the heel of my hand, on a couple.
I will back off 3 or 4 grains and work back up.

Bruce

This message has been edited. Last edited by: RNshooter,

That's too hot a load for me to run if you have to pop up the bolt handle with the heel of your hand.

If the ambient temperature goes up another 10 degrees or the next lot of powder is slightly hotter, you could be in real trouble.

Couple of quick thoughts.

1- Changing brass brand: The main concern is thickness of the brass. You want to weigh some samples of a fired and deprimed FGG and compare to some samples of fired and deprimed LC. If the weight is the same, you should be good to proceed to 2 below.
If the LC is heavier than the FGG, it means it's thicker and that will cause a decrease in pressure in the FGG.
If the LC is lighter than the FGG, it means it's thinner and that will cause increased pressure in the FGG. Danger Will Robinson.

2- A heavy bolt lift is NOT a sign of pressure. I have no idea where people get those ideas. A heavy bolt lift is a sign of overpressure. This occurs because the brass loses its snapback due to the massive pressure. That usually starts to occur at around 70,000 PSI. The harder it is to open the bolt...

In my F-TR bolt rifle, I run heavy loads, above book value. I can open the bolt just lifting it with my thumb. If I ever get any resistance, I would reduce the load. My action has had close to 30,000 heavy loads through it and it's still silky smooth.

3- I have recently purchase 500 cases of Starline brass in .308. I have not had a chance to try it out yet, but from what I observed, it looks great.

I think any knowledgeable reloader knows heavy bolt lift is a sign of overpressure and I'm not sure why that came up.

I didn't advocate checking the brass for thickness as I already knew the answer with respect to the brass the OP is using. I've gone through much the same thing not too long ago.

Actually, if the brass is heavy and thicker, the amount of grains of water it will hold is smaller as is the internal volume, therefore the pressure will increase, not decrease.

https://www.primalrights.com/l...derstanding-pressure

Reading pressure is a required skill that all shooters must have.

A lot number of brass being thicker, thereby reducing internal volume, can increase pressure.

"2- A heavy bolt lift is NOT a sign of pressure. I have no idea where people get those ideas. A heavy bolt lift is a sign of overpressure. This occurs because the brass loses its snapback due to the massive pressure. That usually starts to occur at around 70,000 PSI. The harder it is to open the bolt..."

I'm not sure I follow that. Can you clarify?

Bruce

Starline brass is not easy to find, in stock. I eventually went to Starline themselves and they let me backorder some small primer brass. I am guessing it doesn't require a crazy amount of preparation if Nikonuser is buying it. We will see how it compares to Lapua whenever it shows up.

Bruce

quote:

Originally posted by RNshooter:
"2- A heavy bolt lift is NOT a sign of pressure. I have no idea where people get those ideas. A heavy bolt lift is a sign of overpressure. This occurs because the brass loses its snapback due to the massive pressure. That usually starts to occur at around 70,000 PSI. The harder it is to open the bolt..."

I'm not sure I follow that. Can you clarify?

Bruce

Sure can. I was trying to be cute. It's not a "sign of pressure", it's a sign of over-pressure; you are in dangerous territory.

quote:

Originally posted by Flash-LB:
I think any knowledgeable reloader knows heavy bolt lift is a sign of overpressure and I'm not sure why that came up.

I didn't advocate checking the brass for thickness as I already knew the answer with respect to the brass the OP is using. I've gone through much the same thing not too long ago.

Actually, if the brass is heavy and thicker, the amount of grains of water it will hold is smaller as is the internal volume, therefore the pressure will increase, not decrease.

https://www.primalrights.com/l...derstanding-pressure

Reading pressure is a required skill that all shooters must have.

A lot number of brass being thicker, thereby reducing internal volume, can increase pressure.

You misread what I wrote or I did not express myself properly.

If the LC brass is heavier than the FGG brass, then the same load in the lighter FGG brass will generate lower pressure. The OP was talking about going from LC to FGG so I made my comparisons in the same direction.

Okay, then. So this load is over book and WAY over pressure.
Accuracy be damned, I am backing off 10% before I hurt my rifle or my face.
I will work it back up, from there with Federal brass.
Varget powder and Winchester primers with a 175 SMK on top, by the way.

Thanks,

Bruce

My rule, as I tried to explain, is that if the bolt is not easily opened, the load is in dangerous territory.

So yes, I agree with you, back it off 10%. You will find another node.

I don't care about how primers look and people can debate that to their hearts content. Bolt lift must not be ignored.

I know people who bring a rubber mallet to the line to help open their bolt. Those people are idiots and should be sterilized and sent packing. They're is no lifeguard in the gene pool, but there are signs that must not be ignored.

quote:

Originally posted by NikonUser:


Those people are idiots and should be sterilized

You left out offspring they've already spawned.

Definitely backing off the charge, now

Bruce

Hijacking the thread for another related question. I have had a few pieces of brass do this to me during load development on my own 308 (so far I haven't gone past 40.8gr of IMR 4895) with stuff on the lower end of the charge range. I have been seeing it with certain headstamps but not with others.

I've been attributing them to worn out brass because there's been some shinier spots down by the web, about 1/3 of the way up the case from the head. I can't feel any indication of separation inside the case. I know the headspace is good.

I've been trying to pull those aside and junk them as I find them, but I want to make sure it's not indicative of a larger problem. So far I've fed 3 PPU cases to the channel locks, and I'm thinking about just culling the rest of them (I have 74 total of that brand). Unfortunately there's no way to tell how many firings they have on them.

ETA: I just rebarreled this rifle. I just put a Shilen 25" short chambered prefit on it and used a Clymer reamer to finish it out.

Do what? Make the bolt hard to open with low end charges?

Bruce

quote:

Originally posted by vulrath:
Hijacking the thread for another related question. I have had a few pieces of brass do this to me during load development on my own 308 (so far I haven't gone past 40.8gr of IMR 4895) with stuff on the lower end of the charge range. I have been seeing it with certain headstamps but not with others.

I've been attributing them to worn out brass because there's been some shinier spots down by the web, about 1/3 of the way up the case from the head. I can't feel any indication of separation inside the case. I know the headspace is good.

I've been trying to pull those aside and junk them as I find them, but I want to make sure it's not indicative of a larger problem. So far I've fed 3 PPU cases to the channel locks, and I'm thinking about just culling the rest of them (I have 74 total of that brand). Unfortunately there's no way to tell how many firings they have on them.

ETA: I just rebarreled this rifle. I just put a Shilen 25" short chambered prefit on it and used a Clymer reamer to finish it out.

Your edited statement just answered your question. Provided your question is the one that RNshooter inferred above.

Here is the scenario. You have shooting fired brass that was fired-formed in one or more standard chambers and now you are having ejection issues with that brass in a new barrel that was custom-chambered. What a shock. What would have been more shocking is if the brass had cycled properly.

Around 2007 or so, I was using an Armalite NM M-15 with their "match" 24 inch barrel in F-class competition. I had bought 300 virgin Lapua cases and I was using that as my ammo. At one point, I decided it was time to rebarrel, I had reached the limits of precision of my current barrel. Krieger fitted my upper with a 26 inch cut-rifled barrel and had chambered it with their 5.56-Match chamber. A tight chamber with a long leade for suitable for use with 80 grainers.

When I put in my match ammo, I experienced ejection issues. I checked the cases and all off them had swelled at the base and they would not fit easily in the barrel, or a quality guage. The force of the carrier closing would allow for chambering but after that, it was epic.

I had to sideline all my Lapua brass even after just 2 (or was it 3) firings on them in the old barrel. I tried all manners of small base body dies and F/L small base body dies to try to rescue the Lapua brass. No joy; when that base swell, it's not coming back.

I use small base dies exclusively for my F-class load thinking that the small base helps to retard the expansion of the case at the bottom and rim and thus preserves the primer pocket diameter. Primer pocket expansion is the primary cause of death of my match brass. Using the SB dies I'm pushing up to 10 loadings of what is a very stout charge. The cases all fit nicely in my guage, even after 10 firings.

Even though it's only some brass that is doing it? Like, it's not even half of the majority. I've put 50 rounds down the tube and I'd say 6 have done it. I'll replace all the brass, but the common ground so far is one (of 4 total) headstamp. (For the record, I'm dealing with a Remington 700.)

I've got some new Hornady stashed away that I'll start using instead, and scrap the rest.

I've been using RCBS AR series SB dies. I've got a Redding SB bushing die to replace the sizer (FL, of course), but the bushings I ordered are still in USPS purgartory.