Tuning A 221 Remington Fireball

Another upgrade high on the list was the replacement of the J-Lock, a safety feature that Remington offered for a few years until the roar of disapproval caused its demise. The bolt shroud has a slot shaped like a ‘J’ where a special key is used to lock and unlock the bolt. With the J-Lock it is possible to accidentally lock the bolt without the key, and unless a key is available the rifle becomes useless. Besides making the bolt shroud larger and strange looking many thought it would have a negative effect on accuracy. But the only modification made to a J-Lock bolt was to the shroud, so technically the J-Lock should not affect accuracy.


The firing pin assemblies next to the Sinclair firing pin tool. The assembly on the bottom came with the rifle. The PTG assembly offers a smaller shroud, better spring fit and faster lock time.


The real problem seems to be with the firing pin assembly. For some reason many J-Lock bolts have a heavy firing pin spring that is too long and poorly fitted, and some say this causes trigger resistance, bolt closing effort, and increased lock time (the time span between the sear disengaging and the firing pin hitting the primer).

Replacing the J-Lock shroud and firing pin assembly would be desirable, but would it improve the accuracy of the rifle? There are two sides to this issue: those who think a replacement firing pin assembly is a waste of money because of the small improvement, and those who feel it is an excellent enhancement for the dollars spent. There is no question a replacement would provide a more consistent trigger pull, and this certainly relates to accuracy, albeit only slightly.

Where the disagreement arises is in regards to the benefits of a faster lock time. One company that offers replacement firing pin assemblies points out the flight time of most bullets through the barrel is one to one-and-a-half milliseconds (thousandths of a second), and the lock time of most conventional bolt action rifles varies between 2.6 and 9.0 milliseconds. The replacement firing pin assembly reduces lock time by about forty percent.

So, on a rifle with the faster lock time the bullet has left the barrel by the time the firing pin has reached the primer on most rifles. The result? Since it is almost impossible to hold a rifle perfectly still (especially in the field) the rifle with the standard lock time, when compared to the rifle with the faster lock time, will have moved slightly further from where the crosshair was aiming when the rifle was fired. That’s not much, but it would affect the impact of the bullet, especially at long ranges. This was a good enough reason to replace the firing pin assembly… the fact that the ugly J-Lock would be gone was just icing on the cake.

Of the excellent firing pin assemblies available the choice was determined by past experience and the recommendation of several gunsmiths. Pacific Tool and Gauge (PTG) offers a complete assembly with an aluminum shroud for less than $50 and it provides a fast lock time, better fit and better sear engagement. So, at a price that fit the budget, and given PTG’s reputation for quality, one was placed on order. Once the order was placed Sinclair International was contacted and queried about what should be used to switch firing pin assemblies. Their recommended firing pin removal tool was less than $30 and was placed on order.

When the PTG firing pin assembly arrived it was just as expected, well made and of excellent quality. The Fireball was retrieved and the bolt anxiously removed from the rifle. The Sinclair firing pin removal tool was attached to the bolt shroud. A few turns of the tool dial moved the cocking piece sufficiently so that the firing pin assembly could be unscrewed from the bolt.

With the original firing pin assembly out, a comparison was made to the new one… the rifle did have a heavy firing pin spring that was too long and poorly fitted, so for this reason alone the switch was a good decision. Then the Sinclair tool was attached to the new PTG firing pin assembly and the process repeated, except in reverse. In about ten minutes the assemblies had been switched. The new PTG firing pin assembly and the Sinclair firing pin removal tool was money well spent. The original J-Lock assembly was stashed in the factory box in the event the rifle is sold someday to a collector.

With the physical modifications completed it was time to put together some reloads. The best components would be used, starting with the brass. Since the 221 Fireball is not one of the most popular cartridges one would not expect to find match quality brass but, to my surprise, excellent brass is available through Nosler.

A box was obtained and it turned out to be beautiful stuff, very nicely made. Most shooters are satisfied with the quality of the other brass, but for those seeking an edge in accuracy Nosler is the better choice. It costs a little more but the case mouths are chamfered and de-burred, the cases are inspected and weight sorted, and the flash holes are de-burred and checked for alignment. Basically nothing was required to prepare the Nosler brass for loading; the extra care they take is certainly worth the minimal extra cost.


Nosler 221 Fireball brass and 40 grain bullets.


The original loads that delivered one-inch groups were based on Nosler’s most accurate load for their 40-grain bullet, 19.0 grains of Reloader-7. For those loads the bullets had been seated so the cartridges would fit in the magazine. To determine if the tune-up improved the rifle’s accuracy the same bullet and powder combination would be used, and different bullet seating depths would be tried.

To start the loading process a Hornady Lock-and-Load gauge was used to seat a bullet with the ogive touching the lands. The resulting measurement provided an unwelcome surprise; when the 40-grain Nosler is seated to touch the lands, the base of the bullet is only in the case neck about 1/16 of an inch, barely enough to hold it in place. Obviously Remington did not chamber the rifle to handle a 40-grain bullet. Since the only Remington 221 Fireball ammunition offered has a 50-grain bullet it would make sense that the chamber be designed for that bullet.

Several of the rounds that delivered the one-inch groups were measured and the bullet seating depth measured 0.056-inch off the lands. For the accuracy comparison it was decided the rounds would be loaded identical to those that provided the one-inch groups. At this point I was not very enthusiastic about improving the rifle’s accuracy using a 40-grain bullet. Because of this situation a search for 50-grain Nosler Ballistic Tip bullets was instigated. None could be located, but a box of the 55-grain Ballistic Tips were found… hopefully the few extra grains would not make much difference.

These bullets would be loaded using Nosler’s most accurate load, 17.5 grains of AA-2015, which provides a speed of 2604 feet per second… not very speedy, but the goal is accuracy. The only variation would be different bullet seating depths. As a side note 19.5 grains of this powder can kick the speed up to 2929 feet per second.

The loads that were identical to the one-inch group loads, along with the 55-grain loads, were gathered and taken to the range. As the Fireball was readied on the bench for its first assessment following the tune-up it dawned on me that if the accuracy problem turns out to be the barrel the project has been for naught. But on the brighter side, the rifle was shooting pretty good before the changes were made, and results would be known soon enough.

The targets were placed at a hundred yards and the first rounds down the range were the four groups of 40-grain Noslers loaded with factory brass. Surprisingly, the results looked pretty good. The calipers came up with an average group size of 0.633-inch. Not bad considering the bullets were seated .056-inch off the lands. In any case, that was a nice improvement.

Next up were the four groups with the same load but were loaded using Nosler brass. After firing these four groups I had to rub my eyes when the targets were checked, they actually looked too small. This time the calipers indicated the average group size to be 0.469-inch… and the only difference in the loads was the Nosler brass.


The four groups shot with Nosler Brass.


Those little bullets seemed to enjoy the long jump from the neck of the case to the rifle lands, especially when they were leaping from Nosler brass. Had a benchrest shooter been firing these rounds I suspect the groups would have been even smaller. A big smile came across my face… the goal had been reached; the Fireball is now shooting good enough to be considered a varmint rifle.