6.5 PRC Over pressure with H1000 and 156 Bergers

[Eric Musgrove]

According to Hodgdon the maximum load for 156 grain Bergers is 55.0 grains of H1000 powder. If their calculations were based on Hornady brass, the maximum load for ADG would be even less.

I had no published data for 156 last year when I started so I called Berger and spoke to them based on their info I started at 58 grs of H1000 and worked up, No pressure signs until 60 grs. I fired 58 58.5 59 59.5 and 60....stopped there after 2nd shot heavy bolt lift and ejector mark primer looked ok. They said max was 60.4

 

[Rflshootr]

Every lot of powder, primers, brass and definitely every barrel can be different. Everyone talks about how a barrel gets faster as it gets used. The main reason is because the throat gets rougher, which causes more resistance for the bullet to get started in the bore. With that extra resistance comes more pressure. So the amount of pressure you started with on a brand new nice shiny bore, isn't the same once it gets "X" number of rounds through it and the throat roughens up. Just food for thought.

 

[vancewalker007]

I had no published data for 156 last year when I started so I called Berger and spoke to them based on their info I started at 58 grs of H1000 and worked up, No pressure signs until 60 grs. I fired 58 58.5 59 59.5 and 60....stopped there after 2nd shot heavy bolt lift and ejector mark primer looked ok. They said max was 60.4

Be careful with any case that has an ejector mark on it. I have found with Hornady brass and the Hornady Match FL sizer that the web area of cases exposed to over pressure will not size back down to 0.532 or less. I think you'll find even 0.5325 will close snug in your rifle if you have a SAAMI chamber. I have also found that bumping 4-5 thou instead of the typical 2 thou seems to get most cases back into working size pretty consistently. I've just started tossing anything that will not close smoothly in my rifle. I've have several snug closers that overpressured with loads well below my rifle's pressure point.

 

[GBWS]

Looked at the load data today:
1 fired hornady brass
OAL length 2.945
59.5 Gr H 1000
WLR primer
Berger 156
2936 fps
SD 3
ES 6
Hope that helps your buddy or someone else here.

Eric,
Greatly appreciate you taking the time to do that. Talked to him yesterday and he actually said he didn't hit pressure til 61.1 gr. So did another workup from 57-60.5 because 57.5 & 60 gr shot great. After that workup and his seating depth trials according to info the berger tech gave him. He chose the 60 gr load due to accuracy and velocity he was getting plus good ES/SD.

But, due to it doing what it just did. Told him to back off and work the 57.5 gr load.

Thanks again brother!

Aloha

 

[Eric Musgrove]

Be careful with any case that has an ejector mark on it. I have found with Hornady brass and the Hornady Match FL sizer that the web area of cases exposed to over pressure will not size back down to 0.532 or less. I think you'll find even 0.5325 will close snug in your rifle if you have a SAAMI chamber. I have also found that bumping 4-5 thou instead of the typical 2 thou seems to get most cases back into working size pretty consistently. I've just started tossing anything that will not close smoothly in my rifle. I've have several snug closers that overpressured with loads well below my rifle's pressure point.

thanks I will keep an eye or feel out, I am headed to the range to test the 143 ELDx with some of the same brass and of course I only bumped it back .002 fingers crossed. I did notice the twice fired brass was already passed the max length. So ended up trimming them all.

 

[GBWS]

Be careful with any case that has an ejector mark on it. I have found with Hornady brass and the Hornady Match FL sizer that the web area of cases exposed to over pressure will not size back down to 0.532 or less. I think you'll find even 0.5325 will close snug in your rifle if you have a SAAMI chamber. I have also found that bumping 4-5 thou instead of the typical 2 thou seems to get most cases back into working size pretty consistently. I've just started tossing anything that will not close smoothly in my rifle. I've have several snug closers that overpressured with loads well below my rifle's pressure point.

Aloha Vance
Thanks I've mentioned it to him so he can check his fired brass. I'm not sure what dies he's using, will ask him.

Thanks again

 

[Headzo]

The Velocity you are getting 3136 is 200 fps higher than the data berger gave me for H 1000 60.4grs. You have to respect load data when you are getting velocity so much higher than provided data you can't expect let's say free lunch. And l have load data for 8 powders l have from berger for the 156 and none is over 2986fps that being Retumbo. I will give you an example. I have been developing a load for the 135 classic hunter for my prc 6.5. Using Norma MRP berger powder range 55gr/ 2883. 60.6gr 3157. With Hornady brass l got 3125 with 57gr 3175 with 57.5 and 3220 fps with 58 grs time to stop. . Do l now work up to 60.6 grs l am already 50 fps over Berger max Velocity. I haven't seen pressure signs yet but l am sure if l had continued to up to 60.6 l would have. In ADG cases l get 3170 with 56.7 grs of the MRP. 8 grs less than in the Hornady cases. So same velocity with approx 1 grain less in ADG cases verses Hornady brass. Another quick result breger MRP 53.3/59.4grs 2807/3099fps 140gr hybrid. I reached 3175 with 55.9 grs. I have yet to go any higher as that is what l took to the range to start with. But l am almost at max Velocity already so l am never getting to 59.4 grs that Berger got to in there testing. Sometimes in reloading you may be able to add more powder to match reloading manual data velocity or beat it by small margins by being carefull. But when you are getting max Velocity well below max charge weights you need to recognize that any Velocity gains after that should be done very slowly.

 

[GBWS]

The Velocity you are getting 3136 is 200 fps higher than the data berger gave me for H 1000 60.4grs. You have to respect load data when you are getting velocity so much higher than provided data you can't expect let's say free lunch. And l have load data for 8 powders l have from berger for the 156 and none is over 2986fps that being Retumbo. I will give you an example. I have been developing a load for the 135 classic hunter for my prc 6.5. Using Norma MRP berger powder range 55gr/ 2883. 60.6gr 3157. With Hornady brass l got 3125 with 57gr 3175 with 57.5 and 3220 fps with 58 grs time to stop. . Do l now work up to 60.6 grs l am already 50 fps over Berger max Velocity. I haven't seen pressure signs yet but l am sure if l had continued to up to 60.6 l would have. In ADG cases l get 3170 with 56.7 grs of the MRP. 8 grs less than in the Hornady cases. So same velocity with approx 1 grain less in ADG cases verses Hornady brass. Another quick result breger MRP 53.3/59.4grs 2807/3099fps 140gr hybrid. I reached 3175 with 55.9 grs. I have yet to go any higher as that is what l took to the range to start with. But l am almost at max Velocity already so l am never getting to 59.4 grs that Berger got to in there testing. Sometimes in reloading you may be able to add more powder to match reloading manual data velocity or beat it by small margins by being carefull. But when you are getting max Velocity well below max charge weights you need to recognize that any Velocity gains after that should be done very slowly.

Aloha Headzo
Greatly appreciate the info and response.

I am going to say this as it seems many ppl seem to think it's my load/rifle etc. I put this up for a buddy of mine who reached out to me because he knows I reload a lot. But I don't have a PRC so told him I'd post to see what ppl said.

I have been reloading since 1980 and a lot of the cartridges through the years were wildcats. Cartridges that at the time had no data whatsoever nor all the gadgets we have these days. To develop lots for them etc,, so l kno a little about reloading and l just felt l needed to put it out there. I gave what info he had given me. I didn't talk to berger he did! If they gave you load data that's great! Did they give it to him idk can't tell you. Did he tell me they gave him velocity of the max load...nope! Again I'm just trying to help him out and figure out what's going on. But I'm at the mercy of the info given. Which is exactly what I've shared!

Again just trying to help out I already told him pretty much everything that's already been said in this thread. But still appreciate insight from those with a PRC as l dont load for one.

Thanks all who have responded l appreciate it.

 

[Headzo]

Great you are helping a less experienced hand loader. I started in 1978 so we both have a lot of experience to offer. He will have a mountain of advice when he gets back.

 

[GBWS]

Great you are helping a less experienced hand loader. I started in 1978 so we both have a lot of experience to offer. He will have a mountain of advice when he gets back.

Aloha Headzo
Thanks! Those that know me will tell you I'd give you the shirt off my back to help anyone. Sounds like most here are as well including yourself. Great community for sure!!!

I'll be honest here, I'm still scratching my head a little on this. But, hopefully when he gets back we can figure it out. I feel like something is missing in the info he sent. So just have to wait til he gets back.

Thanks again for your help and insight!

Aloha

 

[sedancowboy]

I think post #19 will solve the problem.

 

[GBWS]

I think post #19 will solve the problem.

Aloha Sedancowboy
Maybe you missed it, it's ALL new brass NOT fired brass. According to him he worked up his load and loaded using all new brass from the same lot.

So Unfortunately, your post won't solve the problem because it's not relevant to the situation.

Thanks & Aloha

 

[TAZMAN]

Bringing up a old thread. I pressured out pretty quick with RL26. I loaded up some H1000 and went up to 60 grains with a CCi200 primer 156 Berger EOL and OAL of 2.955 for mag length. 22 inch barrel with hunter town 308 suppressor. 2978fps but has a very faint ejector mark so I backed down to 59.5 to retest. I use CCI primers sometimes because they seem to show pressure on the primer before the brass has issues. With 59.5 grains of H1000/156EOL I get 2930, 2928, 2935,2936. I think the suppressor and barrel warming up may contribute the speed gain but at 60 grains of H1000 my ES was pretty erratic. My goal was 2900 with a 22 inch barrel so I may back down a little more.

 

[Eric Musgrove]

Bringing up a old thread. I pressured out pretty quick with RL26. I loaded up some H1000 and went up to 60 grains with a CCi200 primer 156 Berger EOL and OAL of 2.955 for mag length. 22 inch barrel with hunter town 308 suppressor. 2978fps but has a very faint ejector mark so I backed down to 59.5 to retest. I use CCI primers sometimes because they seem to show pressure on the primer before the brass has issues. With 59.5 grains of H1000/156EOL I get 2930, 2928, 2935,2936. I think the suppressor and barrel warming up may contribute the speed gain but at 60 grains of H1000 my ES was pretty erratic. My goal was 2900 with a 22 inch barrel so I may back down a little more.

59.5 gr is my load, I had the same pressure signs using Hornady brass WLR primer but I am limited to browning mag length, but still had 2936 velocity...Still way better than factory Hornady 143 ELDX