Rollis Throws A Hissy Fit.

One the challenges in developing a rifle system is finding an accurate load that is precise. This can be a little annoying, if not completely frustrating.

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The RUM, only having 100 rounds through it, is proving to have a lot of precision problems, though the accuracy is showing potential in so far as the rounds are landing near the center of the target. The group size is rather large, or lacking precision. With an end goal of striking targets at over a mile (1,760 yards), groups that are measured in sizes of multiple inches at only 100 yards will not cut it.

After voting I headed to the range with most of my firearms to enjoy them for maybe the last time. I started with the RUM using load number 41, the same that I had been working with for the last several outings. This load has shown some potential, and needing to have as much consistency as possible I decided to stick with it.

The first shot struck one inch left, and one inch low of the point of aim, this would be known as the cold shot with a dirty bore, also commonly known as a cold, dirty. This has been a common occurrence with this rifle. I allowed the rifle to cool  for 10 minutes. The next shot was at least two inches high, and left. Needless to say I was disappointed with the results.

So disappointed in fact that I fired off the remaining 18 rounds. Then I removed the scope, and bagged the rifle up in it’s case then placed it in the bed of the truck where the bad guns have to ride.

The most likely causes for this complete failure will most likely be one of the following.

  1. Scope
  2. Ammunition
  3. Muzzle Break
  4. Barrel

The first thing I did was remove the scope, and test it on the .308 Win. After only a couple sight in shots the rifle was smacking bullseye with it.

The scope, load, and rifle combination has been used on other occasions, and have proved to be both accurate, and precise.

This leaves me confident that the scope is still working fine.

The next item will be to remove the muzzle break,  and then fire 5 more rounds of load number 41 which I expect to perform poorly. Unless it is a simple case of the muzzle break not being compatible with this rifle, which as I have stated before would be a shame. But as with anything firearm related, even though on paper it should work well there is a good amount of voodoo involved in building an accurate rifle.

I will also be trying different brands, and weights of bullets. Sometimes something as simple as a change in bullet weight, or the slight change of the profile of the bullet can produce vastly different results.

The most worrisome possibility would be the need to replace the barrel.

Rifle barrels should be thought of in the same manner as a car tire, there is only so many miles a tire can travel until it is no longer capable of holding the road, and a barrel will only survive a certain number of rounds until the chamber, and rifling is worn beyond its useful life. Some competitors will have to change a barrel out after only 1,200-1,500 rounds in the faster calibers. My hope is to be able to run this barrel at least 3,000 rounds before having to replace it. 

 Having a new barrel mounted would not be very difficult, but the price of even a lower end custom barrel, and the gun smithing it involves would almost be the same as the cost of the rifle itself. and even though at some point in time it will happen I really don’t want it to be in the first year with only 120 rounds down the tube.

 More later. 12/04/2016 Orange Park, Florida. 

The activity for the last couple of days have been interesting.

Arriving home Tuesday night after Susan recovered me from a local McDonald’s after my failure to complete a bicycle ride from the terminal, to the apartment I was greeted by three slobbering dogs, and a dining room table of stuff.

 As I sat on the couch admiring the ammunition that was part of the pile I could feel the pain in my shoulder  already. But that is a later discussion. 

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Norma USA 180 grain Oryx 300 RUM

 Also the scope mount and snap caps were waiting for my attention.

 The next day after taking care of a few things I started with mounting the Wyatt’s DETMAG bottom metal, and five round magazine. I was pleasantly surprised when the parts matched up without any problems. The original stock that this magazine system was mounted on required several hours of fitting before it would work right.  

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Before the mounting of the new bottom metal.
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After the mounting of the new bottom metal.

I tested the functionality with the snap caps and it seemed to be working well, so I started on mounting the Weaver 20 MOA scope base. 

 I cleaned the screw holes, then mounted the mount. First I applied a small drop of gun tight to the new screws then torqued them to 50 inch pounds of pressure. This is where I may have some trouble in the future as the two center screws were wanting to round out. Because of this I did not torque them to the full 50 inch pounds. At some later date the offending screws will be replaced.

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 The next step was to mount the scope. 

 This was a pretty easy task because the Weaver base mount is a rail type that has become a common design feature on all types of firearms in this day and age. We are the better for it also. The scope is already mounted in a detachable mount that is designed for use on AR15 rifles using the same rail mount system.

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 This presents a couple of problems, the most notable is the height of the mount. This causes a poor cheek weld or maybe I should say chin weld. This will be rectified with a more traditional set of mounts in the near future.  

   The scope is a SWFA SS 10x that I have been using for about 18 months. It has a Mil-Quad  (Mil-Dot) reticle and the adjustment knobs are calibrated in 1/10 Mil increments.

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 The cost of this scope at this time depending on the model is anywhere between $300.00 and $400.00 dollars. The fact that it is a fixed 10 power allows the manufacturer to put more resources into the ruggedness and quality of the adjustment knobs, and internal parts making it possible for a new shooter to get into a scope capable of fast adjustments and corrections without having to get a bank loan.

 A U.S. Optics fixed 10x will start at around the $1,200.00 mark.

 I used a set of levels specifically designed for the task of squaring the scope reticle with the center of the bore, then tighten the mounting screws to 20 inch pounds.

 

 All of this took about two hours, having some experience doing these task before allowed me to quickly move through the needed steps, but the most important tool is just that, tools, having the correct tools, and a little bit of experience using them make the job at hand more enjoyable.

 More to come soon.