Pressure signs, lost three primers today

[ColoGuy970]

I am shooting a custom 7mm-300 win mag. The rifle is a PTG blueprinted action with a br firing pin. Connected to a 26" broughton 1:9 twist barrel. Assembled by mirage ULR in Dallas. I am shooting Berger 195's twenty thousands off of the lands. Using H1000 powder, with a federal match magnum primer. Two thousands neck tension. I have almost 300 rounds down the barrel. My first 100 pieces of nosler brass gave out due to primer pockets being too loose. I shot almost all of them three times. So I bought some Norma brass, I also bought some win brass to test out. My max load is 72.0 grains of H1000. I sized the brass and loaded a ladder test in each type of brass. From 68.0gn up to 72.1gn in .3gn steps so I can find the pressure in each type of brass. The Norma kicked two primers in the mid range of my test. The win kicked one out about the middle of my test also. I never had a sticky bolt, I had ejector smudges toward the top of both of my ladders. My FPS was in the 3050fps range at the higher end of the ladder. I need some advice from you all, as I have only been reloading for one year. It shot some pretty nice groups, despite the three primers in the mag well. Thank you for your advice.

 

[ColoGuy970]

 

[FURMAN]

That is way too hot for H1000 and 195s in a 7-100 Win.

 

[Rick Richard]

If you are blowing primers, you are HOT. Back off a couple of grains or so and work back up.

 

[FURMAN]

I would expect 2950 to be an executable speed with H1000 and 195s in the 7-300 win.

 

[Caveman0101]

If you want to get that speed with 195gr bullet try a 28 nosler or 7mm RUM. You are not going to get there with the 7x300win. Or try a lighter bullet if speed is what you need. If you really want to push that heavy of a bullet that fast you should go to a 30 or 338 cal.

 

[FURMAN]

Oh, I think 3050 is doable in that case but you will need RL33.

 

[highdrum]

1:9 twist and 195 at low elevation is a sub par combo. However 3000+ fps is achievable with N570 and RL33 w/o high psi. ADG makes very good 300wm brass as does Peterson, much tougher than Norma. Broughtons are fast barrels on the average. Possibly try the 180 hybrid, or the 184 hybrid F open.

 

[nmbarta]

You flew right past your max load.
You did right by starting low, although I would have started a little lower than you did. (I also shoot a 7x300win with a 1:9 brux, which is better suited for the 180 class bullets)
Everything you said from loose primer pockets after 3 shots, to ejector smudges, to blown primers are all signs of being WAY over pressure.
Reading pressure takes time and learning what to look for can be tough without someone to actually show you.
I guarantee, there were pressure signs way before this happened. Cratered primers, flattened primers, and ejector marks (not smudges) all happen before blown primers.
Be careful man, you're pushing things to hard.
I'm running 175's at 3150. I'm about 50fps below my max load. Your running 195's inside 100 fps of me and my barrel is 2" longer.
Good luck with it, I think you'll have better luck with 175-180's with that twist.

 

[ColoGuy970]

Thank you all for your input and your suggestions. I have had a half assed mentor that likes pushing things way too far. He had a lot of influence on my load data and my expectations, he has the same barrel/chamber rifle. but I have learned a lot from you guys and I really appreciate your knowledge and experience. I still have a lot to learn. I am not trying to shoot laser beams at stuff, and ruin my chamber, go through a barrel in 500 rounds. I started all of my load work with the 195, it shoots well, killed Two animals with them last year, both one shot kills no tracking. It sounds like I need to switch to a lighter bullet, which is fine with me, I am no Berger lover. Suggestions on a bullet to try instead? This is my meat getter I shoot it a lot, but it exists to fill my freezer. Thanks again

 

[FURMAN]

I personally prefer the 175 or 180 Bergers. Take your pick.

 

[brentc]

Oh, I think 3050 is doable in that case but you will need RL33.

I agree with this. Although, 3035 fps is about top end for precision in my 28"bbl with 33.

 

[ColoGuy970]

I am tired of fighting pressure. Where should I start my charge weight with a 180 Berger and H1000? Or should I try RL33 and the Berger 180? This is my hunting rifle so a stable powder is important to me. Thank you all again, I am learning a lot.

 

[mmw194287]

Question for the group as another first year reloader.

In this scenario, if a guy has shot a half dozen over-pressured loads but there's no catastrophic failure, should there be any lingering concerns about the action? Anything you'd look over before starting another round of load development or keep an eye on moving forward?