Need help troubleshooting 300 RUM pressure issue.

[Pdvdh]

The 427 yd group was the third group... put a smile on my face This is with the 96 gr load.

No more pressure "issues", other than the charge weights are low for the pressure/velocities I am seeing.

Those are all nice groups. Glad the rifles are all settling in. Alls well that ends well. Just a worrying barrel break-in process.

 

[Lefty7mmstw]

My analysis to date.

The 6-284 and 6.5 WSM seem to sorta "get over" whatever pressure issues they had. That said, the max loads in volume of powder are slightly lower, by maybe a couple of grains, than the original work up pressure/velocity testing, but are showing the same pressures and velocity. So no loss in velocity performance. The lower charge weights are good as they the max loads are no longer so compressed as they originally were.

In the RUM, I am seeing about equal pressure/velocity with 96 gr of RL33 as I did with 100 gr of RL33 in the original pressure/velocity testing. So something has happened in the bore to cause this and I just don't know what it is. My smith thinks i have removed about 2-3 tenths of a thou of steel from the bore with my lapping. If so, the nitride should be completely gone and would not be a factor.

Here are the 3 pressure work up strings I shot on separate days.

96.... 2937...........2988..........3017
97.... 2963...........3037..........3043
98.... 2962...........3075..........3097
99.... 3037...........-----.........3138
100.. 3105...........-----..........3182
101.. 3121...........3174.........3203 blown Primer
102.. 3162...........3186/3217 heavy bolt on 3217
103.. 3192 slightly sticky bolt

Yesterday's 96 gr velocities averaged about 3100 and are close to max. 98 grains is over max as already demonstrated with a blown primer. I will try 97 gr next and see what happens there for curiosity.

Bottom line, somewhere in the time I got these barrels back from nitriding to now, something happened inside them to change their dynamics.

Montana, you landed one grain over where I am with my hdy 225"s. That bbl. is showing some serious promise with that little cloverleaf you tossed. I hope you've got her figured out so you can get busy shooting it instead of wearing it out settling in on a load.

 

[MontanaRifleman]

Montana, you landed one grain over where I am with my hdy 225"s. That bbl. is showing some serious promise with that little cloverleaf you tossed. I hope you've got her figured out so you can get busy shooting it instead of wearing it out settling in on a load.

Lefty, I have my load so I am good to go. I will be getting some new Bertram 338 EDGE brass to neck down as soon as it gets in stock. I suppose that will require some fine tuning when I start using it.

That said, I have some left over 210 SXR's that Rich (Elkaholic) made for me a few years back and I ran up a pressure string with them yesterday.... very interesting. Got to 101 gr and 3290 without pressure signs. 102 was about 3340 with a sticky bolt and ejector mark. They have a little bit better form factor than the 210 VLD's and not quite as good as the 215 Hybrids. I have 16 more to play with and test for BC.

 

[Lefty7mmstw]

Lefty, I have my load so I am good to go. I will be getting some new Bertram 338 EDGE brass to neck down as soon as it gets in stock. I suppose that will require some fine tuning when I start using it.

yep, saw the other groups come up after I posted... she's good to go...

ever try nosler brass in your rum???

 

[MontanaRifleman]

yep, saw the other groups come up after I posted... she's good to go...

ever try nosler brass in your rum???

I actually started a thread asking about Nosler 300 RUM brass. It seems to be on the soft side from the replies I got. I'm going with the Bertram EDGE brass which I read is as good as Lapua.

 

[Lefty7mmstw]

I actually started a thread asking about Nosler 300 RUM brass. It seems to be on the soft side from the replies I got. I'm going with the Bertram EDGE brass which I read is as good as Lapua.

I've got some my brother sold me cheap when he got out of his 300 rum. it loads the same as remmy brass but will show pressure sooner if you push it. I've got it stuffed with the 95rl33/ 225hdy load also.

We had worked with rl50 and gotten a better vel./pressure relationship than rl33, but the powder compression holding it to mag length was pretty stout. I've got to find another # of rl50 for working with my 7rum. I believe I'm leaving performance on the table working with retumbo.

 

[MontanaRifleman]

I've got some my brother sold me cheap when he got out of his 300 rum. it loads the same as remmy brass but will show pressure sooner if you push it. I've got it stuffed with the 95rl33/ 225hdy load also.

We had worked with rl50 and gotten a better vel./pressure relationship than rl33, but the powder compression holding it to mag length was pretty stout. I've got to find another # of rl50 for working with my 7rum. I believe I'm leaving performance on the table working with retumbo.

Correction: I started a thread on Norma brass (who also makes the Nosler brass)

Yup, I would think Retumbo a bit fast for the 7 RUM and even 33 might be a bit fast until the 195's come out.

Anyway, I'm done with Rem brass in the 300 RUM. Bertram for me.

 

[Kiwi Greg]

I've got some my brother sold me cheap when he got out of his 300 rum. it loads the same as remmy brass but will show pressure sooner if you push it. I've got it stuffed with the 95rl33/ 225hdy load also.

We had worked with rl50 and gotten a better vel./pressure relationship than rl33, but the powder compression holding it to mag length was pretty stout. I've got to find another # of rl50 for working with my 7rum. I believe I'm leaving performance on the table working with retumbo.

I tested 300 Rum brass a while ago now for the Edge.

I tried RP, silver FC, Nosler, Norma & Bertram.

I measured weights, capacity & sectioned all of them.

Nosler is Norma in the 300 Rum, it is soft, but not as soft as FC.

Yes the Bertram shows pressure quick, it is the biggest in the head, so even if you are clearly overloading it, the pockets are still tight, the opposite of FC.

The Bertram brass I had was long & the necks were thinner.

Nosler/Norma gave the best velocity for powder weight but RP would take more powder & so gave the best velocity in the end.

The Nosler/Norma is the "nicest" brass.

I ended up just sticking with RP brass.

This is just what I found for my own piece of mind with the brass I had at the time.

 

[MontanaRifleman]

I tested 300 Rum brass a while ago now for the Edge.

I tried RP, silver FC, Nosler, Norma & Bertram.

I measured weights, capacity & sectioned all of them.

Nosler is Norma in the 300 Rum, it is soft, but not as soft as FC.

Yes the Bertram shows pressure quick, it is the biggest in the head, so even if you are clearly overloading it, the pockets are still tight, the opposite of FC.

The Bertram brass I had was long & the necks were thinner.

Nosler/Norma gave the best velocity for powder weight but RP would take more powder & so gave the best velocity in the end.

The Nosler/Norma is the "nicest" brass.

I ended up just sticking with RP brass.

This is just what I found for my own piece of mind with the brass I had at the time.

Greg, was the Bertram you had the same as the EDGE brass? Was it the necked down EDGE brass?

 

[Kiwi Greg]

Greg, was the Bertram you had the same as the EDGE brass? Was it the necked down EDGE brass?

Sorry, I possibly should have been a bit clearer.

Yes it was Bertram Edge brass.

I made all the brass into Edge brass & tested it in an Edge I had at that time.

 

[MontanaRifleman]

Sorry, I possibly should have been a bit clearer.

Yes it was Bertram Edge brass.

I made all the brass into Edge brass & tested it in an Edge I had at that time.

No apology needed... I'm thinking in 300 RUM and you were talking in 338 EDGE. My mistake.

Did I read you correctly that you got your best velocity out of RP because it had more case capacity than the other brass you tested, including the Bertram, or was that just in comparison to Norma/Nosler?

When reading Shawn Carlock's comparison and testing RP to Bertram, he said the average case capacity for fired RP was 114.3 gr water to 115.5 gr for the fired Bertram. He also said, (which I think you agree with) that the durability of the brass was much better than RP. So... what's not to like about the BB? He is advertising that it will last 5 times longer than RP. Even if it last only 3 times longer, IMO, it is worth it not to have to break in a new lot of brass every 4-6 firings. Are you seeing a different performance level?

 

[Kiwi Greg]

No apology needed... I'm thinking in 300 RUM and you were talking in 338 EDGE. My mistake.

Did I read you correctly that you got your best velocity out of RP because it had more case capacity than the other brass you tested, including the Bertram, or was that just in comparison to Norma/Nosler?

When reading Shawn Carlock's comparison and testing RP to Bertram, he said the average case capacity for fired RP was 114.3 gr water to 115.5 gr for the fired Bertram. He also said, (which I think you agree with) that the durability of the brass was much better than RP. So... what's not to like about the BB? He is advertising that it will last 5 times longer than RP. Even if it last only 3 times longer, IMO, it is worth it not to have to break in a new lot of brass every 4-6 firings. Are you seeing a different performance level?

I got this for capacities, NF is not fired, F is fired


Norma 338 ED 289.7 case 111.7 water NF

Norma 338 ED 290.4 case 115.6 water F

Nosler 338 ED 289.1 case 115.8 water F

Federal 338 ED 279.4 case 116.0 water F

Bertram 338 ED 288.3 case 114.6 water F

Rem 338 ED 274.9 case 116.9 water F

From the brass I compared the RP was the biggest inside.

If I ran the same amount of powder in the Bertram & RP the BB would be looking sad & the RP not, having said that the Bertram pocket will be tighter than the RP, that is to do with the size/diameter of the head I believe.

They all expand to the same size on firing with a decent load.

The FC was the smallest so it expanded the most, 0.0045" IIRC & let the primers go real early.

The BB was the biggest so expanded the least 0.0015" IIRC so the pockets were tight.

I found the BB pockets should basically last for ever, but to get the velocity of the RP (which won't last forever) I needed be punishing the head & shaving brass where as it won't be doing that to the RP.

The best thing to do would be to test it yourself in your rifle to see what you think

I don't have my data on me at the moment sorry.

 

[MontanaRifleman]

I got this for capacities, NF is not fired, F is fired


Norma 338 ED 289.7 case 111.7 water NF

Norma 338 ED 290.4 case 115.6 water F

Nosler 338 ED 289.1 case 115.8 water F

Federal 338 ED 279.4 case 116.0 water F

Bertram 338 ED 288.3 case 114.6 water F

Rem 338 ED 274.9 case 116.9 water F

From the brass I compared the RP was the biggest inside.

If I ran the same amount of powder in the Bertram & RP the BB would be looking sad & the RP not, having said that the Bertram pocket will be tighter than the RP, that is to do with the size/diameter of the head I believe.

They all expand to the same size on firing with a decent load.

The FC was the smallest so it expanded the most, 0.0045" IIRC & let the primers go real early.

The BB was the biggest so expanded the least 0.0015" IIRC so the pockets were tight.

I found the BB pockets should basically last for ever, but to get the velocity of the RP (which won't last forever) I needed be punishing the head & shaving brass where as it won't be doing that to the RP.

The best thing to do would be to test it yourself in your rifle to see what you think

I don't have my data on me at the moment sorry.

Interesting. Well I am tired of the RP brass blowing primer pockets on me. If I had gone through this pressure problem with BB instead of RP, i would probably still have most or all of my brass. As it is, I have few pieces left with a couple of firings left in them and none available to buy of any brand ATM.

I guess I will see how the BB performs when I can get some

 

[Korhil78]

Tikka lover is getting a new shipment of Norma brass in on Friday. Here is the thread in case you Havnt looked. It is the last post on the thread.

http://www.longrangehunting.com/forums/f19/norma-300-ultra-mag-brass-stock-123899/index3.html