The Norma cases that I have been using for the load development are starting to stretch beyond the maximum length point on the Wilson case gauge. Also the number of firing, and reloading cycles are approaching the point that the brass, especially the neck, and shoulder area, are becoming work hardened and will start to crack.
The answer is to anneal the case at the neck, and shoulder area. This is a process of heating the brass to a temperature that softens the metal making it malleable. The main difficulty with this process is heating the neck, and shoulder with out also over heating the lower body of the case near the web of the case where the head rounds ”up” to form the body. Each time the case is used for a firing, and loading cycle the brass will stretch a certen amount in this area no matter what, and if excessive heat is allowed to move into this part of the case during the annealing process the brass can become weak, and a case head separation can occur, ether partial, or full.
In the most extreme cases this could lead to the destruction of the rifle, and injury to the shooter. The one time I had a round suffer a full case head separation was with a M1a (M14) rifle resulting in the following round jamming into the remaining portion of the broken case still stuck in the chamber. This was with surplus military ammo produced in the late 1960’s that I bought, and used in the late 1990’s.
In 2015 I had bought 50 Lake City 7.62×51 .308 Winchester surplus cases that were pull downs, (unfired ammo that has been disassembled, and sold as components), that I used for my Model 700. The case in the photograph was the first one of this batch to crack at the case head, by the fourth loading I had fourteen cases crack, so the cases were retired. This was not a big deal as the cost of .308 Winchester is relatively inexpensive, and many times once fired brass can be found on the ground at many ranges.
Whereas .300 RUM brass is hard to find ether as a loaded cartridge, or as a component, this makes it necessary to take care of the cases a very high priority. With this in mind I prepared to anneal, full length resize, and trim the cases to a uniform length.
First the annealing of the case with a Bernzomatic propane torch by rotating the case with my thumb, and forefinger in the center of the flame until the neck, and shoulder became slightly red. If the lower part of the case would started to become warm I would stop the process. Usually by the time the case started to warm the neck was the right color, and I would drop it in the small bowl of water to quickly cool the brass.
There has been billions, and billions of words written about the need to water cool the brass after annealing both pro, and con. I use the water to cool the brass mostly to keep from burning myself.
Once the cases are annealing, cooled, and then dried, they are then lubed and sized with the full length sizing die instead of the neck sizing die. Finally the cases are trimmed to a uniform length of 2.863 inches.
A short post about this will be put up separately.
Three loads were produced using 168, 175, and 225 grain match bullets. The 168, and 225 are produced by Hornady, and the 175 is produced by Nosler.
The 225 grain bullet is the the heaviest match bullet I can find at this time. I had to be a little creative in my load development by using the the Nosler 220 grain match load data. This can be a little tricky, compared to simply using the load data for one brand of a certain type of bullet with a different brand. Example a Hornady 168 grain match bullet load can with a little due diligence be used with a Sierra 168 grain bullet if you start at the bottom of the data, and work your way up.
The 5 grain difference on heavy bullets like these should not be much of an issue as long as I start at the bottom of the loading charts and work up with small increments looking for overpressure signs.
With this in mind I started with 73.0 grains of IMR 4320, and Federal 215 match primers for the 225 grain Hornady match bullet. The groups were ok, but once again they were not consistent.
The 175 grain Nosler load was made with 83.0 grains of RL22. The first time I have used this powder. The five rounds group was also unimpressive.
The 168 grain match bullet failed to impress also.
During the bullet seating process setting up the bullet seating die with the 225 grain Hornady bullet a sad loss occurred with the first try resulting in the crushing of the neck, and shoulder of one of the Norma cases . This was not because of the longer bullet but was caused when I was calibrating the setting on the die .
I wanted to be able to have the ram of the press in the fully raised position, then run the die down until it bottoms out on the ram. Then I would set the die at this length using the locking ring.
With this zero set all of the bullet adjustment would be a simple process of setting the bullet seating stem to the predetermined mark on the stem.
When starting the process of determining the setting depth for this longer bullet I ran the charged case with a bullet into the die seating the bullet, and wound up buckling the shoulder of the case. A little adjustment using a Canadian Loonie as a gauge on the top of the shell holder created the right amount of space between the top of the shell holder, and the bottom of the die. This will allow me to have a zero setting, and then the ability to adjust the setting stem to the correct setting on the adjustment stem.
This will make keeping consistent, and quick adjustments of the die easy with all the different weight bullets I am working with.
With all this work being done the goals of precise, and accurate ammo should be as easy as 123.
I started the next part of eliminating possible causes of the horrible shot placement with removing the muzzle break. This was a little bit of an adventure. The shop down the street from my home was unable to remove the break due to having broken the tool they normally would use for a break like the one I currently am using.
This left me to take care of it myself, and when I am left to my own devices things can become expensive.
With this in mind I grab a pair of channel locks, (it is strange that a single tool can be referred to as a pair), and twisted on the break until it broke loose. With this work done I remounted the SWFA 10x, and proceed to make some new loads using a different bullet.
I decided to try the 168 grain Hornady hollow point boat tail match, this is a round that I have had a lot of successes with, and the fact that it is the only other .308 bullet that I currently have in inventory also played a major role in this decision.
With the break removed the 175 grain Nosler load still did not perform. The first two rounds were used to adjust the scope, with the third round landing two inches below the bullseye I left the adjustment alone for the next two shots in an effort to create a decent group.
That turned out to be a failure.
Load number 42, and 43 both were made with IMR 4350, wear as load number 44 used Reloader 22. All three have shown great potential, and will be continued to be tested.
First was load 44, that produced a sub 1 inch group with a flier about two inches above the est of the group. I will take the blame for this as I was already becoming a little twitchy because of the recoil.
Load 42, after a scope adjustment, had two shots touching, with shot three, and four producing a one hole group, then a low left flyer.
For the final five shots, four rounds produced two separate two round groups, that were slightly larger than an inch, with the fifth round also producing a low left flyer.
By the end of this round of testing I was done for the day, and went to the handgun range, to enjoy a revolver I don’t spend enough time shooting.
The 175 grain Nosler Custom Competition seem not to work well for me, lucky I only have about 3,200 left.
A muzzle break will be needed no matter what. I will most likely go with a model that ports the gasses to the sides allowing the rifle to move in a more level straight line.
I need to work with my Model 27 a little bit more.
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.
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.
- Muzzle Break
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.
After finishing the channel enlargement I immediately threaded on the muzzle break. I did expect a change of impact from the established 100 yard zero, but I was surprised that it was a 1 mil adjustment to the right with only a slight horizontal adjustment being needed.
With that said the mental anguish was only getting started.
The first shots fired with the new break were larger than expected, also I was testing two different loads at the same time, which complicated the process even more.
I decided to start my next season at the bench with a clean barrel, and a load that already shown potential to be accurate, and I also made 10 more rounds of a new charge weight that is pretty close to the maximum charge.
The cleaning, and loading were done during hurricane Mathew. Susan, and I rode out the storm at our apartment in Jacksonville. We live far enough away from the where the worst winds were going to hit land. We did have a full tank of gas, and extra just in case we needed to bug out at the last minute. This wasn’t necessary, and I was able to get all these things finished, and ready to go as soon as the storm, and it’s effects had passed.
The first shots with the clean barrel, and muzzle break were fantastic, if you consider patterns that look like they were fired by a blind, drunken monkey good.
Needless to say I was a little disappointed, and contemplated removing the break in fear of the break causing odd harmonics of the barrel. This would be sad because of the great amount of reduction in felt recoil.
The first ten rounds were fired in two groups both of which were open, and inconsistent.
The next range season started out poorly also, then the last two rounds landed almost on top of each other in the same spot of the fourth round fired in this group of six. These three rounds were about a half inch of the second round fired. With two rounds that were about an inch from the bullseye, one to the left, one to the right, this six round group became a four inch group.
Then the last five rounds just opened up back into a horrible group.
I suspected that my shooting form was bad. My suspicion was that by placing the bench rest too far back on the stock that was causing the rifle to pivot during the shot in part because of muzzle break pull off caused by the air column in front of the bullet traveling through the muzzle break before the bullet itself travels through the break. Depending on the design of the break this effect can be very hard to control, and predict.
Even though this may be a factor, it is not the root cause.
This afternoon I was able to get the barrel channel of the stock sanded, opening it up quite a bit. I used a D cell battery and some 80 grit sandpaper. The project took about 2 hours, and has come out well.
Some people may think it is opened to much, but I like the ideal of plenty of air getting all around the barrel. Also at some point this barrel will burn out and when this happens the next barrel will have a no taper profile. This will mean it is at about two inches in diameter. Basicly a truck axle.
The look seems to be pretty clean, and even. I did not have anything to refinish the laminate wood so it will be left in the raw. This should not be a problem.
After completing the job I assembled the rifle with the Wyatt’s floor plate again with the same results so I went back to the internal box magazine once again.
What is the definition of insanity again?
09/30/2016, Orange Park, Florida.
In 2014 I started a project with a Remington 700 SPS in 7mm Remington Magnum. This was a pawn shop find that was going to be a long range rig. The SPS models are the base level guns produced by Remington with the lowest quality stocks available.
I have had these stocks become hot enough to become very soft, to the point that it feels tacky as if it is going to melt.
The first thing I did was buy a Bobby Hart laminated stock, and a Wyatt’s magazine system. Then I spent Fourth Of July 2014 watching River Monster marathon, and fitting the bottom metal for the magazine system into the new stock.
At the end of 2014 I sold a large portion of my collection to clean up some debt. The 7mm was part of that sell off, but the stock and magazine system stayed.
Fast forward to this project. The first thing I did when I walked in the door with the .300 was to set the box down, and take the dogs for a walk, then start cooking dinner. But after all that was done I stripped the factory stock off and tried the Bobby Hart out for size, and it work just fine. Though I did decide to leave the Bell & Carlson on it for the time being.
I also mounted the magazine system.
After a couple of month of use the magazine system was not working out. The magazine would drop down a fraction of an inch and cause feeding problems, most often the round would nose dive into the receiver just below the chamber.
As I have been writing this I also have been studying Wyatt’s website and have found this is a common occurrence if the front pillar is too long, which would just need to be sanded, or ground slightly to fit properly.
Unfortunately both the B&C, and the Bobby Hart stocks have a full aluminum bedding blocks, which will require some serious work to bring them into the needed tolerances to work with the magazine system, which means that it is back to the factory installed magazine, and floorplate.
With this decision I also reinstalled the the Bobby Hart stock, and did the dollar bill test, and it failed.
The dollar bill test is a simple way to see if the barrel touches the stock at any point, and even though the bill did slide the whole length of the barrel it was dragging the entire time. This is easily fixed buy some judicious sanding of the stocks barrel channel.
I will have this completed the next time I am home.
For some reason this post has taken quite some time to create even though it was pretty straight forward. Maybe too much going on, and not being especially creative was working against me this time.
09/26/2016 The Corbin Ky Love’s Truck Stop.