Cursory Review of James River Receiver
I don't know the legal structure of the new Rock-Ola Firearms company or the players involved. I was simply asked to give an opinion by Mark Hartman, owner of James River. I have no financial interest in the outcome and do not play favorites or sugar coat reviews.
Following is a cursory view. The next step is to have the guys in the shop assemble a complete rifle with the receiver and report their findings to me. I've done many of the steps required to begin a build process, but I want the guys in the shop to do the final build because it's a chance for continuing education and it gives me a second and third opinion.
The Rock-Ola receiver, serial number 49, when initially inspected has many machining characteristics that are similar to the 7.62mm receivers we've used and inspected here in the shop. For example, the bolt relief cut in the heel of the receiver is executed in a similar fashion, and the left bolt lug recess relief cut was done with three operations using an end mill just like the 7.62mm receivers.
There are dimensional differences. On the Rock-Ola, the external op rod rail is narrower, the edges are not broken on sharp corners and the overall machining finish is not as well executed. On a scale of 1 to 10, the machining is a 6. Time is money, and doing a lot of the fine tuning is often considered unnecessary and unprofitable. This is external and the appearance is always determined by the eye of the beholder.
Other obvious characteristics include the serrations for the rear sight, which do not follow the print. This however is a popular style among all other makers with the exception of LRB. I'm going to have my machinist look at the mag well, but I see tooling marks from a broach type cutter as opposed to the more modern EDM process. There is nothing particularly wrong with that process, but EDM is better in terms of the finish. (Edit to add) The EDM leaves a scale, but once the scale is removed, the final finish is more uniform.
Following are few things that I observed in my cursory inspection:
1. Barrel timing and threads
The receiver has advanced thread timing. This means the barrel hand times in an advanced position. Of course this is dependent on how one views it. It could be considered a retarded position. Regardless of terminology, I compared the timing on this receiver to a USGI receiver and several others and the bottom line is that the barrel will need to be turned back significantly in order to stay within the torque limits of the receiver and obtain proper timing. My estimate is 10 degrees advanced. The threads also do not terminate at the proper place verified by comparison and by examining the print. I was not able to identify a major issue with this lack of thread termination. The threads continue all the way into the front of the mag well instead of terminating .100" or so short.
2. Firing Pin Bridge
The firing pin bridge is substantial, but lacks a proper ramp for the firing pin tail. While a slight bevel is present, it's not within specification. It does not meet the requirements outlined in the print. Furthermore, the relief cut for the firing pin tail is tight and the firing pin will not fully seat when the bolt is in full battery. Of course after the hammer hits it a few times, it will seat, but this may alter the dimensions of the firing pin tail. I recommend a modification be made to bring this area into specification.
3. The bolt relief cut at heel
This is a complex machining operation that requires fixtures to hold the receiver in perfect alignment. On USGI receivers, it is purported this operation was done through the face of the receiver with a cutting tool long enough to make a cylindrical relief cut on the inside of the heel to allow the bolt to contact squarely so that the force is evenly distributed during recoil. It appears the relief cut on this receiver is done very similarly to the 7.62mm receiver in that it was cut on an angle coming into the workpiece from the opening in the bolt race behind the receiver legs. The machining marks in this area are nearly identical to the 7.62mm receivers. Even the type of rough cutting tool was used.
4. Bolt stop boss spring pin holes
The through holes for the spring pin that holds the bolt stop are slightly undersized. Using a pin gauge set, I determined them to be .0946". This makes for extra work and opening this up to .0950" would make a tremendous difference. This dimension must account for the addition of the final finish.
Things that are well executed:
1. Given the complex nature of forging, machining and heat treatment, this receiver has a good to very good overall appearance. The finish is a deep black and appears to be very similar to a black nitriding finish.
2. The left bolt lug recess has the appropriate ramp for bolt rotation and the left lug recess has a good radius. The trigger groups I tried all lined up and there were no issues with clearance when locking the trigger guard.
3. All bolts I tried in the receiver worked without binding. (contact will be determined when the build is done) The bolt stop window was adequately machined and the rear sight pocket was spot on. Alignment and overall diameter on the rear sight ears was excellent.
4. The op rod track dimensions are very good as well as the dismount relief cut, or notch.
5. Scope mount compatibility was good.
Overall assessment and suggestions for improvement:
My overall impression is good. It's obvious a lot of time went in to not making many of the same mistakes others have made in the past. The machining and geometry are average and very good respectively. Aside from the items above, and from a cursory view I believe the receiver has potential. I didn't look at it and say "daxx that's the best receiver I've ever seen" but it is a good first run receiver. If those who are making the receiver will spend some extra time cleaning up the machining, breaking the sharp edges and fixing the areas notated above. The receiver will be a solid option for those wanting a forged receiver.
I'll follow-up with an additional review after the receiver has been built and test fired. As I continue my evaluation, I'll update this post.
