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7SAUM Build - Ritten Precision (***Updated***)

Barney88PDC

Sergeant
Full Member
Minuteman
Aug 22, 2009
783
147
Ft.Worth, TX
I contacted Mr. Ted Torres of Ritten Precision about a build I would like to have done. He stated that he would be happy to do so but did not have a reamer in the caliber I wanted to build in. I let him know that we had a few months to work with as this was going to be a hunting gun for Colorado and that I was not going until November. So we agreed to find out what we would need and get the parts ordered.

We both did a little research and agreed on the dimensions of a reamer we would use. I wanted to ensure that I would have proper freebore length for the Berger 168 and 180 VLD’s and the proper neck diameter so I would not have to neck turn my brass. We settled on a .3185” neck and .180” freebore reamer from PTG and after a few months it came in so we could begin the build.

The caliber I chose is 7SAUM and my parts are as follows: Surgeon 1086 action (I went LA so that I would have plenty of room to seat the VLD’s out long and not restrict case capacity as well as reliable feeding), Krieger SS 1:9 RV contour barrel with a JEC Muzzle Brake, McMillan Game Scout stock molded in McMillan Camo, Badger Aluminum M4 bottom metal and a Jewell trigger.

Ted contacted me last week stating that the reamer had come in and we agreed to meet over the weekend to put it together. I have known him for a few years now and I asked if it would be possible to witness the build. I tried to say in the background and keep my mouth shut as much as possible as I realize he was doing this for me as a favor. I did not want to break his concentration and I know I do not like people watching me work so I tried to not ask too many questions or interrupt him while he worked.

When I arrived he had already taken the measurements of my action and had them listed on a nice diagram that included a drawing of the action and barrel as well as the dimensions of the action he acquired using his various micrometers and calipers. So when I arrived we were ready to begin the cutting operations.

He began by putting the chamber end of the barrel in the lathe and dialing the barrel in with a Grizzly rod and a proper bushing. You select the proper bushing by feel as there will be slight resistance when the proper size is installed. The bushings come in .0002” (2 ten thousands) increments and I was amazed how that little change was very noticeable. With the proper bushing installed on the Grizzly rod we were able to indicate the barrel in fairly quickly. Ted started by indicating in to within one thousandth with one dial indicator then swapped to a finer one that is accurate to one ten thousandth. He dialed the barrel in to within one ten thousandth of an inch at two points 2” apart. The Grizzly rod was held in place with a drill chuck in the tail stock. We would move the Grizzly rod in and out of the barrel 2”, dialing in the chuck with the rod at one position, then dial in the rear support with the rod in the other position. Going back and forth checking the runout with the rod in both places until the reading was within one ten thousandths.

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Next step is to turn down the portion of the barrel that will become the tenon to the proper OD. Using the diagram Ted already filled out we had the desired dimensions in front of us the entire time. After the OD was turned the next step was to cut the tenon threads for which the Surgeon 1086 calls for 16 TPI. He swapped cutting tools to a thread cutter and after making several passes and taking smaller and smaller bites Ted was able to get a very nice and snug barrel to action fit. The next step was to cut the tenon to length and time the action. He put a micrometer on the muzzle end of the barrel that was sticking out the opposite side of the lathe and found the highest point of the muzzle. When the barrel torqued to the action you want the high spot to be at the 12 o’clock position. To do this he screwed the action on and determined how far off the timing was. He then determined how much we would need to set the shoulder back allowing the action to screw on further to time correctly. Once the action was properly timed he cut the excess tenon off the back to have proper length.

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Next operation is to cut the bolt nose recess. This will allow for the proper clearance between the barrel and bolt nose once installed. Before this step and actually between every step we would reinstall the Grizzly Rod and check to insure that the barrel was still running true. This was the only time I would jump in and help was by dialing the rod back and forth the 2” inches in the tail stock while Ted was turning the head stock and checking the dials.

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Next was to cut the actual chamber. We checked alignment again then swapped out the fixture in the tailstock to one that would support the reamer. The reamer was brand new and made a very nice clean cut of the chamber. He would cut his desired depth then retract the reamer to clean off the chips and shavings, blow out any debris in the barrel and reapply more cutting oil to the reamer. Ted took ever smaller bites as we neared the final dimension of the chamber. He continually would screw the action on to the barrel and check the chamber dimension with Go / No-Go gauges measuring the gap between the action face and the shoulder of the barrel tenon. This told us how much we lacked before we got really close to the final dimension. He would then apply fresh cutting oil to the reamer and make another cut. Once we got really close Ted was taking very small bites between checks, 0.001” and less at a time. He was cleaning out the chamber with patches and a pistol rod to ensure no debris or cutting oil was affecting the measurements. Once he got the bolt to barely close on a Go gauge he put a piece of scotch tape on the back of the gauge which increased the length by about 0.002”. This was going to be the take up that the action would see once we torqued the action on to the barrel with the required 100 lb-ft. He then made one final cut and now the bolt would barely close on the Go gauge with tape but would close freely on the Go gauge without tape. He swapped cutting tools again and made a few slight chamfers to the tenon, bolt recess and chamber then took the barrel out of the lathe and torqued on the action. Ted was right on and now the bolt would not close on the Go gauge with tape but would close on the Go gauge without any tape. He also checked to make sure that the bolt would not close on a No-Go gauge. These checks and attention to detail assured us we had a nice tightly fit chamber. I also had made a few dummy rounds that I brought and we chambered one of those as well to ensure that the bolt would close freely.

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Re: 7SAUM Build - Ritten Precision

Next we cut off about 1” of barrel from the muzzle end. During finishing at the barrel manufacture they lap the barrel and this end can be out of tolerance. Most smiths recommend cutting off a portion to ensure that the bore of the muzzle and crown are tight and have not been affected by the lapping rod during finishing processes. I have also read where making this cut in the lathe with a cut off tool can induce stress and a possible choke point at the crown. So a cut off saw is the desired method.

Next was to cut the crown and thread the muzzle for a brake. We installed the muzzle end of the barrel in the lathe and dialed in the OD to face off the barrel in order to clean up the rough cut from the cut off saw. Now that the burrs from the cut off saw had been removed we could dial in to the bore using the Grizzly rod with the proper bushing and dial indicators like we did on the chamber end. Once we were within one ten thousandth Ted followed that up by turning the OD down to 0.625” for the 5/8” x 24 threads needed for the muzzle break. Once the proper shank length and OD were established he swapped out the cutting tool again in favor of a thread cutter. He once again cut the threads making very shallow cuts and several passes, cleaning up all of the chips and checking the fit every pass. Once the threads were cut to the correct depth he put on the brake in order to time it correctly. It needed to rotate about an additional 160 degrees so he bumped the shoulder back the necessary amount. I asked him to recess the crown to help prevent possible damage. After this operation we then cleaned off any oil that remained and applied some thread sealant and secured the brake onto the muzzle.

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The final step was to put the springs and pins into the bolt and action to complete the build. Here is the metal work all done with the barreled action ready for some Cerakote. The coating should be done in a few weeks right about the time the stock should show up from McMillan. Stay tuned for final build pictures.
 
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Re: 7SAUM Build - Ritten Precision

Once the machining work was done the metal headed off to Diablo Rifle Works for a Patriot Brown Cerakote job. I was originally going to go with Flat Dark Earth but in some of the pictures on Cerakote’s website FDE looked lighter than I wanted. It really is hard to tell how the color is truly going to look from one picture to the next as the cameras used and the lighting conditions that the pictures were taken in are different, but I am very pleased with color. It looks like FDE indoors and like a milk chocolate brown outside in direct sunlight.

The stock is a McMillan Game Scout. Basically it is their HTG stock with a vertical grip. So if you are looking for a light weight hunting stock but want to maintain an A5 style grip I highly recommend picking one up. I ordered it in McMillan Camo and bedded the action myself. I do not feel like the actual camo in the stock and the picture of the McMillan Camo swatch on their web site is 100% representative of one another. I really feel McMillan could use some updating to their website with quality pictures of actual stocks in the camo choices they offer. I do however still like the pattern as it will blend in nicely with the natural terrain I will be hunting in.

The rifle with optics weighs 10.5# on a bathroom scale. 12.25# with bipod and stock pack.

Here is the finished build with a picture of a test target from load development with 4 shots on the top target and 3 shots on the bottom. The orange circles are 1” diameter and both groups are under ½”. I spent a lot of time and effort doing load development and acquired data that I posted in the reloading section. If you have a gun in this caliber you may want to visit it. http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=3562795#Post3562795

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Re: 7SAUM Build - Ritten Precision

I finally settled on a load (Nosler Brass, CCI BR2, 65.5 H1000, 180 Berger Hunting VLD 0.015" into lands) and needed to go get DOPE at distance. This was the first time I shot this gun past 200 yards. All groups were 3 shots.

I needed to zero the scope for this load so I started at 100 yards. Here is the frist three from the day with a 1" orange dot. 0.664" - 0.284" = .380"

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This is from 300 yards with a 2" orange dot. I aimed right edge for a slight quatering wind but didnt need it. I also guessed on the elevation and was 3 clicks too high. 1.184 - 0.284 = 0.900" 300 yard group.

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500 Yards the orange reactive flapper is 7.5" in diameter. Shots are the grey marks at approximately 2:00, 2:30 and 3:30

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1000 yards. Not a great group but the two on the right were consistant. Target is an ISPC which is 18" wide.

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Re: 7SAUM Build - Ritten Precision

Great write up Bannon! Thanks for the kind words. The proof will be on the paper and I can't wait to see how that thing shoots. I'll have that reamer chewing more steel soon for a personal hunting rifle before long.
 
Re: 7SAUM Build - Ritten Precision

Ted did my barreled action and he also has my Glock 17 slide for some non-standard machining. Ive only known him for a little while, but have no doubts leaving my stuff with him. Ill to hurry up and finish my cerakote so I can get some pictures of his work.
 
Re: 7SAUM Build - Ritten Precision

What a shooter. Great looking rifle - congrats. I have a 338 LM being built by Robert (RWS Gunsmithing) and I decided to go with the McMillian camo too. It's good to see your completed project turn out so nice - maybe mine will too!
 
Re: 7SAUM Build - Ritten Precision

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: squin</div><div class="ubbcode-body">Very nice build.  How do you like shooting from the tripod?  </div></div>
 
Honestly I just got the HOG SADDLE and have only shot off of it once standing. From that position it is not as stable as I had imagined it would be. Part of that is I do not have the best tripod and with the angle of the legs at about 20 degrees from vertical and them being at full extension it is not very stable. Now I did do some dry fire parctice the other day with the legs spread apart further at about 60 degrees from a seated position and it was much more stable. I had a discussion with another shooter who just picked one up and we both had the same opinion. He said he was banging steel at 800 from seated and prone with his but from a standing postion it was much less stable.
 
Defenately a nice peice of kit but know how to use it and know its limitations. YMMV.