A little stumped load development virgin brass vs once fired

[Shane Lindsey]

How many rounds do you have on the barrel.. has it sped up yet?

I have a 7mm that shoots 160 partitions. Virgin brass and new barrel was 70.5 grains Retumbo @3015 fps
2nd/3rd fired brass I had to back down to about 69 grains and velocity was about 2950-2960. 69.5 was too much pressure.
After about 140 rounds and the barrel sped up i had to back it down to 68.8 and velocity settled in about 2960-2970.

I wish Peterson would make their "long" brass is the 7mag too.

 

[jraulsten]

That was what I thought to. Initially I was only loading to 56.5gr. Then I also had some Berger 153.5's. Called Berger and they told me 57.0 min to 63.3 max Retumbo, I thought the guy was on Crack called back another day and talked to a different guy he told me the same thing. Told him that the case will not hardly even hold 63.3 he said that it was a compressed load. I actually got to 62gr before pressure signs on the virgin brass. That is when I decided to tried pushing the A-Tips a little more and came up with the 60gr load for both the Bergers and Hornady bullets.

This really concerns me about Berger because I recently had the same experience.

In the past, I have always received pretty conservative load data from Berger. Not long ago I called requesting 300 PRC load data for 215 Hybrids and N570. The starting load I was given was more than the max I ended up with pushing the 215s over 2900 FPS. Thank goodness I knew from experience and researching multiple other sources that the data I was given was insane.

 

[Wyo220]

I am pushing 215s over 3000 FPS with the obsolete old school belted 300 win mag and h1000. Only shoots less than 1/2 MOA so there's that. Sorry. Can't resist.
Kyle

 

[jraulsten]

I am pushing 215s over 3000 FPS with the obsolete old school belted 300 win mag and h1000. Only shoots less than 1/2 MOA so there's that. Sorry. Can't resist.
Kyle

One in every crowd....

 

[orkan]

This is the third time I've heard from customers telling me that Berger is handing out insane load advice in the last 6 months.

They really need to get reigns on whoever is doing it. They are going to get someone hurt.

When testing this bullet, I hit pressure around 2900fps with almost every powder tested. 3125 is certifiably insane.

 

[Shane Lindsey]

This really concerns me about Berger because I recently had the same experience.

In the past, I have always received pretty conservative load data from Berger. Not long ago I called requesting 300 PRC load data for 215 Hybrids and N570. The starting load I was given was more than the max I ended up with pushing the 215s over 2900 FPS. Thank goodness I knew from experience and researching multiple other sources that the data I was given was insane.

They are using quickload I believe. At least that is what the tech told me. Not sure they shoot them.

I was given data from them for my 300 RUM and the 245. It seems to be correct. I could not get to the powder charge I was given, but I hit pressure a few grains below it. When I settled on the load, the velocity was still above their top end given with less powder.
I think in this case they were using Norma brass for the QL workup, I was using Rem and ADG.

 

[huntnidaho]

Speaking of Berger's load data -slightly different bullet but the load data Berger sent me for the 156 EOL and Retumbo is the same charge weights mentioned earlier in this thread 57-63.3. Max velocity is listed at 2986fps in a 26" barrel. Seems reasonable on the velocity side of things as a max. Most powders in the load data they sent have maxes in the 2800fps to low 2900fps range, Retumbo being one of the higher velocity performers. FWIW, they also sent me load data for the 140VLD. I started with minimum listed charge weight of H1000 @56.5 grains. My velocity was 2730fps over 9 shots, they listed 2750fps. Seems to be tracking pretty close for me. Sorry if this is too much digression.

 

[milboltnut]

Ok so I was working on a load with virgin brass for my 6.5 PRC. Found a good node at 3125 with 153 Atip, 60gr of Retumbo, and Winchester Mag primers. Prepped my 1 fired brass I dropped down to 59.5gr and immediately got pressure signs, heavy bolt lift ejector marks and flattened primers. Went home and decided to start my load work up again. Now I get pressure signs with anything above 57gr of Retumbo and velocity only 2970. Barrel is clean with no carbon ring, checked with bore scope. I'm stumped as I was really happy with 3125 but now my good node is only at 2950. That's a big drop in velocity.

That's a big drop in velocity.

really ? seriously ?

 

[naja302]

Yep you are way over pressure initially (like most of what I see in forums). Virgin brass doesn't show pressure signs like once fired stuff dies.

 

[284ackley]

I know it's hard to do these days due to short supply of most components, but if possible, I usually try to do load development with fireformed brass. I'll typically (but not always), fire 50 rounds as a break in while playing at the same time, then start load development with those cases

Ditto

 

[milboltnut]

I know it's hard to do these days due to short supply of most components, but if possible, I usually try to do load development with fireformed brass. I'll typically (but not always), fire 50 rounds as a break in while playing at the same time, then start load development with those cases

I would assume you would want to, to find out where you're at accuracy wise.

 

[jtvann]

Yep you are way over pressure initially (like most of what I see in forums). Virgin brass doesn't show pressure signs like once fired stuff dies.

I did not know that. I was just working up a load for my 300 wsm using new ADG brass. Never saw any pressure signs on the brass, but felt a slightly heavier bolt lift across the last grain and a half up to the published max.

My results of OCW were all screwy, probably because it was new brass. So now I've fire formed all 100 that I'm going to use.

Are you suggesting that I start over and repeat everything, including the pressure test starting from minimum to see if I have signs now that my brass is once fired?

 

[nealm66]

I use the Hornady tool for measuring the base to datum on new brass and if there's more than 3thousands difference, I will fireform before load work up. Otherwise, there's always a difference because of the expansion. Sucks but at least you can use some cheap bullets and powder your not fond of to get it done

 

[Mike Matteson]

You are up over the reloading manual call out for max loads. I generally go over the books call out. (that's me, but I am very careful) If the case is in the 70gr area, I move up at the rate of .5 gr at a time. (note I start out with the manual low load first) I load only a single case and step up the next .5gr until I see flatten primers, no creators, or ejector makes. (So say that not correct, but that's what I do) New case need to be fireformed, and a new barrel need to be used. Now your rifle. It's about a 60gr case. If I go up above there max load, I only go up at the rate of .2gr at a time. Watching for pressure signs. You didn't state if you are in the lands or back off. When fire forming your cases, use a reduced load and set up with the bullet into the lands .003 to .005. That way your case base is push against your bolt face. That makes the shoulder move forward to form to your chamber with out case stretch at the base. This stops the case from moving back, and forces the case at the shoulder to move forward to fit the chamber.
All can I say is, I have learn a bunch by staying on top of what is written here over the years. Put a lot into my reloading steps. All to the better.