bigngreen
Well-Known Member
Did the smith check the throats before it went in for nitriding?
Need help troubleshooting 300 RUM pressure issue.
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MontanaRifleman
Well-Known Member
No... he did look at the 6-284 throat and bore when it got back and said it looked fine. I'm not too concerned about the conditions of the throats. I babied them in the break-in and got a very good feel for how they were doing. They do foul a little, but not much and a scrub with a few wet patches of BTE cleans them up quick.
After the copper and carbon are gone, I will patch out the ferrous oxide if I use IOSSO. BTE does not get it out much but IOSSO will.
buckbrush
Well-Known Member
Did you lap the snot out of the barrels after nitride and before shooting them?
MontanaRifleman
Well-Known Member
buckbrush
Well-Known Member
I spoke with a barrel maker a while ago that sends a lot of barrels for nitride treatment. He stated that they should be lapped very vigorously after the treatment and before shooting. He stated that if you don't feel like you are hurting the barrel, you aren't doing it enough. JB Bore Paste and minimum 1/2 hour.
This may not be your problem..just a thought. I've also had weird results with Alliant powders when nearing max pressure...which it sounds like you are very close to. RL15 and my 35 Whelen IMP got very scary very fast. A 1/2 grain
jump in powder above slight primer cratering resulted in a face full of gas and the primer in the mag box.
Good luck. I hope you get it worked out and post the results. I have a barrel going out for nitride treatement soon.
MontanaRifleman
Well-Known Member
Thanks,
I spent a good half hour on each of these barrels, then scrubbed a again after firing a couple of rounds through each per someone else's routine. Before firing, the ferrous oxide came off on the patch as a brown color. After firing, there was no more brown, but there was a black substance of very similar consistency that I assume is the ferrous oxide.
My smith will be having a look today or tomorrow.
Outlaw6.0
Well-Known Member
I'm wondering what your GS is going to find. I'm very interested to see how this turns out for you. My first thought was carbon ring... not enought rounds down the tube for that.
My money is on some remnants of the nitriding process is causing your issues.
Best of luck Mark, i'm sure it'll sort itself out.
t
My money is on some remnants of the nitriding process is causing your issues.
Best of luck Mark, i'm sure it'll sort itself out.
t
Lefty7mmstw
Well-Known Member
tag.... interested in results
The only thought I have on this is you aren't giving your bullets much run to the rifling. Crowding top charge and a rough start to the ballgame( assuming the nitriding needs to be polished more) could be causing the bullets to nearly stall out as they engrave. That's not good when you have just lit 100 grains of nitro. I'd be interested in pressure testing here (like the pressure trace II); it would take all the guesswork out.
The only thought I have on this is you aren't giving your bullets much run to the rifling. Crowding top charge and a rough start to the ballgame( assuming the nitriding needs to be polished more) could be causing the bullets to nearly stall out as they engrave. That's not good when you have just lit 100 grains of nitro. I'd be interested in pressure testing here (like the pressure trace II); it would take all the guesswork out.
dodgefreak8
Well-Known Member
I was really considering nitriding but now I'm not real sure. I guess I'll keep an eye on this and see what you come up with. Good luck!
varmintH8R
Well-Known Member
Also tagging in. Very curious to find out the issue.
Good luck Mark, I hope it works out.
Brandon
Good luck Mark, I hope it works out.
Brandon
MontanaRifleman
Well-Known Member
Here is the latest. I made some phones calls to H&M, a gun builder that does a lot of work with H&M black nitrded barrels, and Tim North, owner of Broughton Barrels. And took the rifles to my smith a couple of times for bore scoping.
In the first chat with H&M I explained the pressure problems I was having and they said they hadn't heard anything like that before. Also said they were not experts on those types of issues and gave me the number of a gun builder who did a lot of work with them who they said was an expert. Also said, it might not be a bad idea to patch out all the ferrous oxide and that I should probably not be able to harm the barrels.
So I proceeded to start round 2 and lap the snot out of the 300 RUM and 6-284 barrels and put about 80 patches through the 6-284 and about 100 patches through the RUM, double/triple stroking each patch impregnated with IOSSO. And each patch brought out black ferrous oxide right up to the last patch I pushed through the bores. Took a couple hours or so on each barrel.
Then I called the gun builder and told him my story and he said that he hadn't heard or experienced anything like this either and said he had used and had experience with hundreds of H&M black nitrided barrels including his own personal guns. He suggested that I use an ultra sonic tank to clean them. He also said H&M did this (which I already knew) after treating the barrels and some residue still stays in the bore. He said if he thought there was too much left, he would send it back for more ultra sonic cleaning. He advised against using an abrasive, which is what everyone else advised me to use… reason being, you can never get all the abrasive grit out of the bore. He would use a wire brush and solvent and patches to get it where he wanted it and never really patched it all out. Said, in time you would end up just shooting it out. So I stopped patching out the rifles and did not start round 2 on the 6.5 WSM
I load up a few rounds for each rifle. Did another workup string for the RUM from 96-102 gr of RL33 pushing 230's and loaded up an accuracy velocity/pressure string of about 10 rounds with 100 gr of RL33 and 230's and a workup string with GSC 177's using Retumbo.
Before stopping at the range I take them in with clean bores for Glen (my smith) to check out past Sat. He looks at them and in his opinion they were very smooth… probably too smooth and much smother that a brand new custom hand lapped barrel. He showed me both through the bore scope and I could see what he was talking about. The inside was a bright stainless steel color and I was told by H&M, it should be a silvery black color. The throat and bores on each one showed signs of heat cracking (alligator skin pattern) which he said was normal looking for bore with their round count. This was not completely surprising to me as I had heard, the bores are wear resistant but still subject to heat cracking and had planned not to shoot them hot… however, these bores had seen a lot of excessive pressure rounds through them.
So I take the 6-284 and RUM to the range to shoot yesterday. Sat was too windy. I start with the RUM and shoot one of the 100 gr rounds and it records an MV of 3142 with a nice easy bolt and I think to myself, I can live with that. Then I start the work up string starting at 96 gr allowing cooling between shots on a gusty day with 35* temp. Cooling was no problem. When I get to the 100 gr round, it records an MV of 3182, fairly easy bolt. Hmmmm… a jump of 40 fps from the first 100 gr round. Then I shoot the 101 gr round resulting in a heavy bolt, big shiny ejector mark and powder ring around the primer. Tap the case head on the shooting table and primer falls out. This work up string showed higher pressures/velocities per charge than the previous strings. I hesitantly load a 100 gr round for pressure/velocity check and get 3178 with a sticky bolt and ejector mark. Load another, and get 3198 with a heavy bolt, ejector mark and powder ring around the primer. Done with that and disappointed the reduced 100 gr load was pressuring out. Then I run the Retumbo/GSC 177 string up through 101 gr with a peak velocity of 3477 and nice easy bolt. I was expecting to pressure out around 99-100.
Then I start with the 6-284 and 63.5 gr RL33 (a 1/2 gr step down from previous "max") with 105 hybrids. Velocities in successive order…
3496
3511
3521
3528
3558
3548
3586
A clear trend of increasing pressure but no external pressure signs.
100 gr CEB's with 63.5 gr RL33
3584
3623
3584
3586
3599
A fairly stable string with one little spike.
Pack up head back to do some more loading to return again with reduced loads. I am thinking maybe I just need to foul these barrels and shoot less powder. I load up 8 at 98 gr RL33/230 hybrids and 8 at 101 gr Retumbo GSC 177's. Then load 63 gr RL33 (reduced by ½ gr) strings for the 105's and 100's and head back to the range.
I start with the RUM and quickly pressure out @ 98 gr RL33/230 hybrids with 2 shots. Then try the 101 Retumbo GSC 177 load, 2 shots with MV's in the 3500 fps range, then remove the Magneto for accuracy group testing. Put 2 shots about ½" apart on a gusty windy day, then the next one blows a primer and lands an inch high. I try another and get a sticky bolt. Put the Magneto back on to check velocities and they are running about 3550 with stiff bolts. Done with the RUM.
Load a 63 gr RL33 105 hybrid round and Boom…. heavy bolt. Done with that string. Load a 63 gr RL33 100 CEB load and Boom… heavy bolt. Done for the day.
This morning I call H&M to explain I am still having pressure issues and explain I don't think it's the treatment but probably something I have done since getting them back. Also describe what Glen and I saw in the bore scope and the tech said it sounded like I had started removing steel. He said they could redo the barrels at no additional cost. I said that I would probably try that. But first I wanted to make sure I hadn't lapped it too smooth.
Then I call Tim North on my way to Glen's and explain everything and ask if he thinks it sounds like I have over lapped the bore too smooth? We talk quite a while about everything and I put him on with Glen and they talk awhile. They think "maybe" the RL33 is laying down too much dirty carbon on the smooth bore (33 burns fairly dirty). While I was talking with Tim, Glen scopes the clean 6.5 WSM that has not been excessively lapped and reports (and shows me) that the bore looks like a new custom hand lapped bore, not as smooth as the other two. It looks normal and has a little darker hue. Glen then scope the fouled 6-284 and RUM bores. They were fouled but could not say for sure that it was excessive. They both cleaned up easy. Of note…Tim mentioned to Glen that he thought he (Tim) had also overlapped a couple of nitrided bores in the past.
So the plan is to try Retumbo only loads in the 6.5 WSM and 6-284 for comparison and see if that lowers the pressure curve. Will accomplish tomorrow. Also, will probably runs a few Tubb's final finish pills down the smooth tubes to rough them up a little and possibly remove any irregularities I may have lapped into the bores before sending in to H&M for retreatment.
Bottom line, visual inspection showed nothing unusual in clean or fouled bores. Overall, they were in good shape other than the overly smooth bores. The pressure issue is still a mystery.
In the first chat with H&M I explained the pressure problems I was having and they said they hadn't heard anything like that before. Also said they were not experts on those types of issues and gave me the number of a gun builder who did a lot of work with them who they said was an expert. Also said, it might not be a bad idea to patch out all the ferrous oxide and that I should probably not be able to harm the barrels.
So I proceeded to start round 2 and lap the snot out of the 300 RUM and 6-284 barrels and put about 80 patches through the 6-284 and about 100 patches through the RUM, double/triple stroking each patch impregnated with IOSSO. And each patch brought out black ferrous oxide right up to the last patch I pushed through the bores. Took a couple hours or so on each barrel.
Then I called the gun builder and told him my story and he said that he hadn't heard or experienced anything like this either and said he had used and had experience with hundreds of H&M black nitrided barrels including his own personal guns. He suggested that I use an ultra sonic tank to clean them. He also said H&M did this (which I already knew) after treating the barrels and some residue still stays in the bore. He said if he thought there was too much left, he would send it back for more ultra sonic cleaning. He advised against using an abrasive, which is what everyone else advised me to use… reason being, you can never get all the abrasive grit out of the bore. He would use a wire brush and solvent and patches to get it where he wanted it and never really patched it all out. Said, in time you would end up just shooting it out. So I stopped patching out the rifles and did not start round 2 on the 6.5 WSM
I load up a few rounds for each rifle. Did another workup string for the RUM from 96-102 gr of RL33 pushing 230's and loaded up an accuracy velocity/pressure string of about 10 rounds with 100 gr of RL33 and 230's and a workup string with GSC 177's using Retumbo.
Before stopping at the range I take them in with clean bores for Glen (my smith) to check out past Sat. He looks at them and in his opinion they were very smooth… probably too smooth and much smother that a brand new custom hand lapped barrel. He showed me both through the bore scope and I could see what he was talking about. The inside was a bright stainless steel color and I was told by H&M, it should be a silvery black color. The throat and bores on each one showed signs of heat cracking (alligator skin pattern) which he said was normal looking for bore with their round count. This was not completely surprising to me as I had heard, the bores are wear resistant but still subject to heat cracking and had planned not to shoot them hot… however, these bores had seen a lot of excessive pressure rounds through them.
So I take the 6-284 and RUM to the range to shoot yesterday. Sat was too windy. I start with the RUM and shoot one of the 100 gr rounds and it records an MV of 3142 with a nice easy bolt and I think to myself, I can live with that. Then I start the work up string starting at 96 gr allowing cooling between shots on a gusty day with 35* temp. Cooling was no problem. When I get to the 100 gr round, it records an MV of 3182, fairly easy bolt. Hmmmm… a jump of 40 fps from the first 100 gr round. Then I shoot the 101 gr round resulting in a heavy bolt, big shiny ejector mark and powder ring around the primer. Tap the case head on the shooting table and primer falls out. This work up string showed higher pressures/velocities per charge than the previous strings. I hesitantly load a 100 gr round for pressure/velocity check and get 3178 with a sticky bolt and ejector mark. Load another, and get 3198 with a heavy bolt, ejector mark and powder ring around the primer. Done with that and disappointed the reduced 100 gr load was pressuring out. Then I run the Retumbo/GSC 177 string up through 101 gr with a peak velocity of 3477 and nice easy bolt. I was expecting to pressure out around 99-100.
Then I start with the 6-284 and 63.5 gr RL33 (a 1/2 gr step down from previous "max") with 105 hybrids. Velocities in successive order…
3496
3511
3521
3528
3558
3548
3586
A clear trend of increasing pressure but no external pressure signs.
100 gr CEB's with 63.5 gr RL33
3584
3623
3584
3586
3599
A fairly stable string with one little spike.
Pack up head back to do some more loading to return again with reduced loads. I am thinking maybe I just need to foul these barrels and shoot less powder. I load up 8 at 98 gr RL33/230 hybrids and 8 at 101 gr Retumbo GSC 177's. Then load 63 gr RL33 (reduced by ½ gr) strings for the 105's and 100's and head back to the range.
I start with the RUM and quickly pressure out @ 98 gr RL33/230 hybrids with 2 shots. Then try the 101 Retumbo GSC 177 load, 2 shots with MV's in the 3500 fps range, then remove the Magneto for accuracy group testing. Put 2 shots about ½" apart on a gusty windy day, then the next one blows a primer and lands an inch high. I try another and get a sticky bolt. Put the Magneto back on to check velocities and they are running about 3550 with stiff bolts. Done with the RUM.
Load a 63 gr RL33 105 hybrid round and Boom…. heavy bolt. Done with that string. Load a 63 gr RL33 100 CEB load and Boom… heavy bolt. Done for the day.
This morning I call H&M to explain I am still having pressure issues and explain I don't think it's the treatment but probably something I have done since getting them back. Also describe what Glen and I saw in the bore scope and the tech said it sounded like I had started removing steel. He said they could redo the barrels at no additional cost. I said that I would probably try that. But first I wanted to make sure I hadn't lapped it too smooth.
Then I call Tim North on my way to Glen's and explain everything and ask if he thinks it sounds like I have over lapped the bore too smooth? We talk quite a while about everything and I put him on with Glen and they talk awhile. They think "maybe" the RL33 is laying down too much dirty carbon on the smooth bore (33 burns fairly dirty). While I was talking with Tim, Glen scopes the clean 6.5 WSM that has not been excessively lapped and reports (and shows me) that the bore looks like a new custom hand lapped bore, not as smooth as the other two. It looks normal and has a little darker hue. Glen then scope the fouled 6-284 and RUM bores. They were fouled but could not say for sure that it was excessive. They both cleaned up easy. Of note…Tim mentioned to Glen that he thought he (Tim) had also overlapped a couple of nitrided bores in the past.
So the plan is to try Retumbo only loads in the 6.5 WSM and 6-284 for comparison and see if that lowers the pressure curve. Will accomplish tomorrow. Also, will probably runs a few Tubb's final finish pills down the smooth tubes to rough them up a little and possibly remove any irregularities I may have lapped into the bores before sending in to H&M for retreatment.
Bottom line, visual inspection showed nothing unusual in clean or fouled bores. Overall, they were in good shape other than the overly smooth bores. The pressure issue is still a mystery.
MontanaRifleman
Well-Known Member
Thanks, I think the vast majority of customers are very happy. I'm guessing this is the result of something I have probably done.
Thanks Brandon
IdahoRedneck
Well-Known Member
Montana, for curiositys sake have you tried retumbo in the 300 ultra, that may tell ya if its a powder issue with re 33, if youve already discussed this sorry I missed it.......
MontanaRifleman
Well-Known Member
Yup Dan, I have with the same results. RL17 also. My smith and Tim North think maybe the RL33 is contaminating the bore ahead of the Retumbo. So will try Retumbo on clean bores with the 6.5 WSM and 6-284
