My freshly rebarreled 7mm wsm is on its way ! :D

[Shrek]

I haven't tried Talley Lightweights in years but in the spirit of lightening things up I used them here. I've seen debates about lapping the Talley mounts but I decided I would lightly lapp them. WRONG ! I ended up lapping the bejesus out of them ! I had less than 10% contact after about 20 twists on the lapping bar. Ended up reapplying lapping compound three times and tightening 5 or 6 times. Back bottom was about 90% contact and front bottom about 70% when I quit. Tops never made more than 50% contact but I was afraid I'd run out of travel before I got a good mate on the tops. The tops are thin and should conform some. I think Talley doesn't recommend lapping so people won't know how out of spec their rings are. Unlapped they did line up the bars almost dead on so the lapping wasn't to cut a straight line but to correct out of round and very uneven inside ring surface.

 

[JustOneMoreShot]

Wow. I'm shocked because I always hear such good things about the Talleys.
The build looks real nice so far.

 

[Shrek]

Wow. I'm shocked because I always hear such good things about the Talleys.
.

I was too. I'd heard of them failing sometimes but not needing a bunch of lapping . When I put the alignment bars in and they lined up so well I was sure it wouldn't take much to lapp them . Put the lapp bar in and did about 20 turns on it and when I pulled it out I was shocked ! Hardly any contact at all. They would have torqued the scope tube all to Hades !

 

[rayporter]

they probably should still be bedded.

 

[16Bore]

Never lapped a LW, never saw a need too. Don't know why you'd lap aluminum anyway.....

 

[Cahunter805]

Shrek
I lap my Talley's but have never had much trouble with them. Most just need a little bit and that's it.
I usually start by just lapping the bottom and then one light pass with tops on.

 

[Shrek]

I received my magnetospeed and I've been building a half dozen rounds for break in and pressure/velocity testing . 67.0 gr Retumbo through 69.9gr. Not directly related but I started with RCBS calipers and then had Mitutoyo calipers made in Brazil but they disappeared. I was short on cash and bought some used Brown & Sharpe calipers off ebay. The RCBS ones were garbage ! I thought the Mitutoyo's were great but the used Brown & Sharpe swiss made are flat out better ! Dead on the same measurement over and over. The Mitutoyo's were very nice and I would have never looked for anything else if I hadn't misplaced them.

 

[Shrek]

I'm back from starting the break in process and gathering info. Kind of disappointed. Velocity was much lower than I expected. Retumbo pushing a 168gr berger classic in ww brass and wlrm primers. 69gr 2759 , 69.5gr 2808 , 69.7gr 2860 , 69.9gr 2840 . No pressure signs. Powder didn't seem to burn well as I've never gotten so much soot from Retumbo before. Either the powder is degrading due to age , heat , and humidity as its been open for about a year and not kept in a climate controlled storage or I set up my scale wrong and all the charges were 5 gr low. I have an unopened can of H1000 to try and I'm going to look afor some fresh Retumbo. Anyone here with Quickload who would run the projected velocities of the listed loads and five grains lower ? 25.25" barrel.

 

[Shrek]

On a brighter note , the chamber is truly minimum spec. From sized brass that I had to hang on the press handle to size to fired was .0015" growth ! Full length die screwed down solid and hanging on the handle is the proper setback. I'll be ordering a full length neck sizer die and doing it all in one step .

 

[mtnclimber]

wow thats quite low. my 20 inch barrel 7mm rem mag is pushing 168 match bergers with 68 grains of h1000 at 2810fps. Win brass and rem 9 1/2 primer.

 

[Shrek]

wow thats quite low. my 20 inch barrel 7mm rem mag is pushing 168 match bergers with 68 grains of h1000 at 2810fps. Win brass and rem 9 1/2 primer.

That's what I'm thinking. Something isn't kosher and I'm not sure what yet. My leading theory is that I miss counted the marks on my Lyman M5 scale and the actual charges were all 5 grains low. It would explain the low velocity and the poor powder burn. I was shoot one and clean to break the barrel in and in one shot it looked like I had been shooting triple 7 not retumbo. Either bad charge weight or bad powder because the chamber and bore are tight ! I couldn't even begin to push a double patch down the barrel. On my factory Remington 7-08 I can get a double patch down with effort.

 

[mtnclimber]

That's what I'm thinking. Something isn't kosher and I'm not sure what yet. My leading theory is that I miss counted the marks on my Lyman M5 scale and the actual charges were all 5 grains low. It would explain the low velocity and the poor powder burn. I was shoot one and clean to break the barrel in and in one shot it looked like I had been shooting triple 7 not retumbo. Either bad charge weight or bad powder because the chamber and bore are tight ! I couldn't even begin to push a double patch down the barrel. On my factory Remington 7-08 I can get a double patch down with effort.

have you used the powder before in other rifles or is this your first go around with it? was it sealed? how old was it?

better 5 grains too low than too high!

 

[Shrek]

I have decided that there was absolutely nothing wrong with the measures or the powder. I failed to take into account that I'm running a much longer coal and I have a bunch more room in the case , .165" more room. Every Retumbo load that ever shot well was compressed. The load data I was going off was for 2.86 coal and I'm at 3.025 coal. I picked up the loading at 70 gr Retumbo and 68.5 gr H1000. Built 5 each in half grain increments. I'm betting I'll end up even higher around 73.5 gr Retumbo and 71.5 gr H1000 but I'm not rushing up there. It was 97.3ºF in the shade today and when the sun started to hit the bench late it was brutal. I'm going again in the morning and will work through these ten and see where I'm at.
The bedding issue I have one idea to follow. The rear action screw may be bottoming out as it comes tight. I'll take a little off of it if I don't recognize another issue.

 

[Shrek]

I tried some more loads today. H1000 ran into pressure at 70.5 gr and 2908. 71.0 had a little bit heavy bolt lift at 2918. Tells me it's maxed at around 70gr. H1000 is off the list now. Retumbo gave higher velocity without pressure signs so it is what I'm going to work with 72gr gave 2923 and no pressure signs. Still very disappointed with the velocity but the barrel is just starting to break in. Last four shots left much less copper and cleaned easier. A double patch will go down the barrel now also. I sure hope it picks up a 100fps or so in the next twenty or thirty shots. Going for five and clean for the next ten shots and then start running it until accuracy falls off or I can't stand it and feel the need to clean. Has anyone here had a barrel pick up a bunch of speed as it broke in ?

 

[mtnclimber]

Have you thought of using a less hot primer? like a 210m. friends of mine weren't getting the velocity they wanted or compressed loads and by using a cooler primer they were able to get more powder in there and higher velocities.

Happy shootn

 

[Shrek]

That's an idea worth trying. I have some cci 200's on hand and I may see about getting some 250's.

 

[strictlyRUM]

Shrek,

Just a couple hints from a guy who used to get paid to work on guns. If you apply the bedding on the action and in the stock, you wont get the voids. Always put way more than needed if you want it to look purdy. More clean up but you wont have voids or pockets. Also I use the spray on bees wax shoe spray. I think its penguin brand, or at least it has a penguin on the can. It gets in all the cracks and releases better than anything I have used.

I also tend to use colder primers with the slower powders. I steer clear of Retumbo though. H1000 is much more stable and better speed as well as accuracy. RL17 also does me very well for consistancy and speed. Also I have done lots of 7 WMSs and most dies are like yours for some reason. If a guy wants minimum spec chamber than I will tell them we will most likely have to take about .005-.010 off the bottom of the die to get a full length size. Dont ask me why. Just happens.

All in all I have gone to the RSAUM for my seven short needs. Easier to find brass and feeds better in most cases. It will also get you the same if not a tad more speed from 10 grains less powder. There is a big difference in feeding, powder burn, and accuracy between the 30 degree shoulder and the 35 degree shoulder. Just look at the 6mm BR. Also if you blow out 300 or 270 WSM cases, your neck is going to be a good bit shorter than the 7WSM when said and done. But it will work if absolutely needed.

Sorry to hear about your headaches. A good smith is hard to find. Most now a days are gun plumbers and dont understand the fine details of machining or customer service.

Jason

 

[Shrek]

StrictlyRUM , I think I agree about a wax as a release agent and I'll look at the spray bees wax. I've done a few bedding jobs and I've gotten ok at it. The Model 70 with its flat sides has me buttering up the action as well as the stock with bedding. I still can't see why the barrel is now a little off center but the only thing I can think is that the high nineties heat and direct sun heating it while in rested on its side on the bag caused a slight warp because there is nothing I can find in the actual bedding. No loosening or cracks. I guess I'll grind it out and do the whole thing over because the #4 barrel doesn't leave much room to sand in a McMillan Edge . I can fix the stock but the lower velocity is really bugging me.

I don't know if you saw my other build thread but the next project is a 6.5 saum. A few financial hits have slowed that down but right after this season I'm putting it together.

 

[Sam Millard]

I tried some more loads today. H1000 ran into pressure at 70.5 gr and 2908. 71.0 had a little bit heavy bolt lift at 2918. Tells me it's maxed at around 70gr. H1000 is off the list now. Retumbo gave higher velocity without pressure signs so it is what I'm going to work with 72gr gave 2923 and no pressure signs. Still very disappointed with the velocity but the barrel is just starting to break in. Last four shots left much less copper and cleaned easier. A double patch will go down the barrel now also. I sure hope it picks up a 100fps or so in the next twenty or thirty shots. Going for five and clean for the next ten shots and then start running it until accuracy falls off or I can't stand it and feel the need to clean. Has anyone here had a barrel pick up a bunch of speed as it broke in ?

Wow! That seems mighty slow for that stiff charge of H1000. I get 2950 w/ 68.0 in a 26" Hart (which is slower than a lot of barrels). WW Brass/CCI 250/168 HVLD.

Yes, all of my barrels shoot 30-40 fps slower with a cold, perfectly clean barrel. I don't start testing or practicing until there are 5-10 down the tube. Get that sucker dirty and leave it there! None of the Harts I run have picked up speed as they "break in".

 

[Shrek]

Sam , that's what I thought. Really slow. I'm going to find all new powder to try and some 250 cci primers. If it weren't for the fact that my 7-08 came in about where I thought it would I would suspect the Magnetospeed . A 3 groove lilja has the reputation of being a fast barrel so it's even more puzzling. All the Retumbo I've tried has been open for a while. I threw the 1/4 lb I had out but got a half pound from a friend but he didn't know how long it had been open. The H1000 is about a year old also and I'd opened it last year and looked at it and put it away so it could be degraded also. I'm grasping at straws at this point because none of the powder smells or looks bad. Chamber is a tight minimum chamber so I don't have a clue at this point.