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Discussion in 'Gunsmithing' started by rscott5028, Jun 9, 2011.
Or, is it more correct to say that I braked it?
Can't wait to shoot it!!!
RScott...You were right the first time... that is a pretty aggressive broke fer sure. Hopefully you "tamed" it at the same time.
What method did you use to dial in your barrel? Grizzly rod, bushed range rod, indicate the diameter, the bore? Lots of ways to get there. Just wondering what you chose.
I used a #2 Grizzly Rod and bushing from Pacific Tool and Gauge that just fit the bore.
Now, the rest of the story is that this was a lot of work and I'm not certain that I really went about it the most efficient way and I'm open to suggestions. So, here's what I did.
I dialed it in to <.0001" using a Mitutoyo with the bushing just inside the muzzle and then 3" deep. ...alternating in and out until it was dialed in for both locations.
Once I was within about .010" of the calculated maj/min dia, I started taking .001" cuts until I was just able to thread the break on by hand with anit-seize to prevent gauling. I guess I should really use the compound to feed in at 29-30 deg, but I went straight in using the cross-feed and the threads look/feel clean with no discernable chatter.
Next, I removed the barrel and chucked the brake dialing in the OD and faced it back to where the OD at the end of the brake matched the OD at the shoulder on the barrel and removed the first 2 threads. Doing so boogered the lead thread and I didn't have a small enough inside thread tool. So, I had to clean up that lead thread by hand.
The OD and amount of facing was based on where I had calculated that the tapered barrel and tapered muzzle should meet up with the same OD and still allow the muzzle to come within about .060" of bottoming out inside the brake.
When I took it out of the lathe and assembled it, the timing was about 1-2 degrees over rotated. Feeling blessed that it had worked out like that on the first attempt, I let that slide and went ahead dialed in the barrel bore and drilled the brake with a .260" bit and reamed it to .2877" for the .264 bullets. (6.5x284)
Finally, I polished the brake with 400, 600, 1000, 1500, and 2000 wet/dry plus WD40 at 1400 rpm in the lathe after covering the ways with aluminum foil.
That 1-2 degrees is really eating at me and I'm thinking I'll need to go back and fix that before I'm truly done. I was just confounded as to whether I should face some from the shoulder, the brake or both in order to have the OD match up at the intersection. ...or, not worry about it and just turn the OD of the brake to match the barrel using the compound rest after timing it.
It just seems like I did a lot of re-chucking and re-dialing. Any suggestions for an easier method of procedure would be appreciated.
My first one is clocked just past and it's all I can do to ignore it. I've been clocking them slightly ahead and it seems that after taking them of a few times they are perfect.
I've been using the Griz rod to line it all up as well and the results seem good to me, I don't take the barrel out till it's finished though. I don't do much figuring I crown it, cut the tenon a little short and thread it for a snug fit then cut the shoulder deeper to clock it then open up the hole and taper to blend into the barrel. I've got it down to about 1.5-2 hrs from start to finish.
I've gone into a brake fitting frenzy after doing the first one, love doing my own work!!!
Sounds like some good pointers there.
Wow Richard! You are a man after my own heart. Why just do good enough when perfection is possible. Proper thread technique is to use your compound set at 29 - 29-1/2 and keep your cross feed set to zero as a reference.
To time it up it will be far easier to dial in the barrel and cut the shoulder back. Reason I say this is you don't have to dial in that brake and start from scratch for each trial fit. I have fit brakes to prethreaded barrels and it is a pain to rechuck an item to try to cut .003" Using my DRO and going off my last cut I can take .0030" exactly time after time. I have .0002" resolution in my DRO. On timed brakes I only thread and sholder the barrel to come up 2 turns short. This gives me 2 tries at the timing before I have to recut the muzzle back. Rather than relieve the brake it is just as easy to cut a .060 relief to run your threads off into. You are going to have one anyway if you need to time.
Factory installed brakes from Weatherby and Remington are all the same way.
Here is one I did recently that started out with a .060 relief and it ended up right at 1 o'clock on the first try. You can see I just took my cut off tool and plunged right back in the amount I needed to clock up.
Here it is all timed up and Cerakoted to almost match the factory matte on this Weatherby Sporter.
FWIW: I fit these for what you paid for that brake alone.
Thanks for the great pointers. I like and trust Darrel Holland's products. But, I'm open minded. I couldn't get to your website??
FWIF: This brake cost me about $8k. The next one should be considerably less expensive.
Next time you go about this, thread your barrel, set the shoulder back on the barrel thread to 'time' the brake to it, bore the brake out to the proper diameter (single point) and then (with the brake installed) dial in the outside of the barrel and blend in the back of the brake with the compound set to the proper angle... No need to go turning off the back of the brake. You should only have to chuck up one item to install a brake, and that's the barrel.
That's what I'm gathering from the recommendations.
The brake had a frosted finish to begin with and I wasn't sure how it would polish and I don't really like polishing on the lathe. So, I was hesitant to turn the OD of the brake.
I think it worked out in the end. But, I've learned a few things here that should help out next time.
I finally finished bedding the rifle and took my son out to shoot it yesterday.
I fired 2, one after bore sighting and one after correcting elevation and windage.
The brake works like a champ.
My son put the remaining 6 142g SMKs for that load in one ragged hole @100yds.
The rest of the loads were with various seating depths and varied up to .75".
I think it's ready for long range practice and I can't wait for him to nail a deer this winter. ...not sure if we'll use SMK or switch to Berger.
Thanks for the help/pointers!
Looks like a nice brake. Cut the holes last after the barrel has been torgued to the action and the brake torqued to the muzzle. Zero rotation alignment problems every time. Plus or minus 10 seconds is good enough. As long as you centered off the bore useing a spud you should be good to go. I use a minnimum hole diameter of .040 over bore size. In my opinion the baffles also need to be crowned, but crowning them is my preference, I think they're a bit quieter that way and a little easier to tune a load.
I use .020" over bullet diameter. I never have tried looser. I have read that tighter is supposed to be more efficient but have never personally tested them. How did you come to settle on .040"?
Same here... I thought closer tolerance within reason was more effective at diverting gases through the baffles and thus reducing recoil with correspondingly more noise being a principle byproduct.
...as compared to suppressors that largely convert the pressures to heat rather than noise.