#swinglockdies

As the test showed, Full-Form bullet sizing offers --at the very least-- advantages of higher and more consistent muzzle velocities. In that particular test it also showed the highest precision with a 10-shot group of 1.035 MoA. This was not a surprise to me because in several guns Full-Form sizing has proven to give up better precision than Smooth-Form sizing.

My Remington 700ML with McGowen .451″ barrel was pretty forthcoming with good precision. I could just Full-Form a bullet with a single pass, push it down with one hand, and shoot little groups. That barrel did not require indexing of the bullet; if you are unfamiliar with the term it means aligning the bullet at the muzzle so that the formed bullet is matched to the exact groove corresponding to it. This was not an issue; just push bullet through brake, twist until it dropped into the barrel, and push to seat.

Having said that, it did not happen that way with my Hankins gun. Full-Form sizing for that Brux barrel would leave some bullets hard to seat. It turns out that on the lands of this barrel one or two of them have a small flat. If you look at the picture below you can see what looks like a groove just above the green dot on the punch. That is a flat in the land, the grooves are lined up with the red dots on either side of the green dot.

Some makes of dies seem to be better (Swinglock namely and it’s patented) and so do some barrels. Brux makes good barrels but not every barrel is going to be perfect. I had to figure out a work around to get this die and barrel in concert because I was determined to make Full-Form work in this gun due to the performance advantages it offers.

I began to index all the bullets but it was still spotty as to how consistent my bullets fit the barrel. On the range it was causing mayhem with my precision and accuracy. I might shoot three or four shots through one ragged hole then pitch one or two shots an inch and half or two out of the group. Being the kind of guy who immediately looks at myself instead of my equipment when I fail I let this go on for a few weeks trying to work through it. I spent a lot of time with a small bore gun working fundamentals and hit the range again to no avail. Certain it was not me I began tweaking bullet sizing and powder charge. I completely re-assembled the gun to make sure there were no issues. Nothing improved. 

Whenever I can’t figure something out I talk to people who are smarter and more experienced than I am. I usually find out there is still nothing new under the sun and that there is a viable solution someone else has figured out. In this instance the recommendation from my buddy Rob was to size the bullet two to three times, rotating the bullet each time. The idea is that it is still Full-Form so a much more occlusive seal than a Smooth-Form but by rotating it you eliminate the sensitivity to indexing. You can just find a land/groove orientation, the bullet pushes past the crown, then you ram it home.

The question I had was, “How do you do this without having a bullet with twelve to eighteen grooves in it?” After a brief explanation via text message I had a grasp on how to get it done.

If you take a look at the punch (protruding from the top of the die) you will see one green witness mark and two red. The green lines up with the witness mark at the bottom of my die where the bullet enters (couldn't get a good pic). Luckily, I had my Full-Form bushing inserted in the die where a land was lined up facing me. If you have a fixed bushing die you just have to mark it where you can see a land to work with.

When you mark your punch I recommend that you spot drill it. If you don’t your mark will wipe away. Drill it or punch it then paint it. You need to mark your bullet the first time as well (I used green since my first dot was green). After you size the bullet you can re index the two marks (one in punch and one in a land) then mark your grooves. Again, I recommend that you spot drill your grooves and paint them or you will lose your marking.

If you look at the two red dots both are aligned with the left edge of the groove they correspond to. That is how far the bullet rotates in one pass. When I make the second pass I turn the bullet 180° (or half the total number of grooves in your barrel) and line those two red dots on the inside right edge of the rifling to take into account how they enter the die. If you feel any resistance that feels like initial forming stop and use a dowel to punch out from the top instead of cutting a larger groove. Another technique is to use a piece of tubing and run it through the top of the die towards the ram, force it over the bullet tip, then pull up and index it into the die before applying force with the ram. Either way, if you index it into the rifling it will just sail smoothly through on the second pass.

That said, if you cut a larger groove I have not found it to be a deal breaker. I have shot a slew of sub-.5 MoA groups using bullets that had a slightly enlarged groove from 2 passes from the FF die. I still segregate them though if I mess it up and will use them as my cold bore bullet (I actually believe it is usually a “cold shooter” but more on that another time) or bullets I use for shooting from alts even though there is no practical difference in precision or accuracy.

Loading does not require the removal of a brake as some think. You either have a funnel made/modified for full-form use or if you are stuck with a break made for smooth form bullets you improvise by using a pieced of tubing. You stick the bullet nose into the tubing and use the tubing (run through the funnel) to pull the bullet ogive into the base of the funnel so that you can use the funnel to insert the bullet through the brake, index it to the rifling, and lightly seat it before using the ramrod to finish the job.

Note: I am now  also addressing the Inline Muzzle-Loader also because I have had a number of people approach me and ask if the Kinetic Performance BOMB can be used in guns that use Black Powder or Substitute Black Powders like Pyrodex, Triple 7, and Blackhorn 209. The answer is YES for those who have wondered. We have had customers use them with sabots and sabotless with BH209 with great results. The discussion that follows is applicable to an Inline Muzzle-Loader except that SMOKELESS POWDER CAN NEVER BE USED.

A Smokeless Muzzle-Loader (SML) or Inline Muzzle-Loader (IML) is not a whole lot different than a center-fire (CF) rifle in regard to its need for quality ammunition. In regard to the next couple of posts in this series there is no difference between an SML and IML as it pertains to loading. The main difference between the two is the need to clean between shots with subs and the fact that an SML eliminates that need.  Both the SML/IML and the CF have its unique advantage over the other: the ML removes some of the ammunition variables by virtue of the absence of a chamber and the CF gun removes some of the ammunition variables by removing the shooter/loader. Assuming you have a well built gun ammunition is the key to optimizing accuracy and precision.

From a mechanical standpoint the advantage goes to the SML/IML every time. As mentioned above, there is no chamber which means there is no brass case.That is to say, you don’t have to figure out case body sizing, neck tension, jump, eliminate run-out, etc.

With a CF you don’t have to worry about load compression (only in regard to repeatability not pressure generated). In general, most loads are not going to have enough load density to compress powder in a metallic cartridge and don’t need to because neck tension and engagement at the leade build the pressure. In an SML/IML compression is required. If you were to load a compressed load the advantage goes to the CF because all your ammo is loaded on a press with mechanical limits so your loading density would be more consistent than if you were to load by hand pressure as you do with an SML/IML.

Why do I bring up this comparison? If you had an SML/IML and a press that could load your gun we wouldn’t even be having this conversation. Instead, you have a human loading it. Guys struggle to figure out how to load a SML/IML properly, become frustrated with their gun, and never get the level of performance they want without ever getting closer to achieving it. That was my experience in the beginning.Your SML/IML has all the advantage over a CF and if you feed it properly you will be blown away by the level of accuracy and precision you can obtain.

With the SML/IML you really only have to nail down two things: bullet fit and charge weight. I listed bullet fit first because it is the most important. It is the most important because it is directly related to the human factor of loading the SML/IML. I keep saying accuracy and precision are the keys.

Let’s define those terms. Accuracy is your ability to get extremely close or exactly match a selected standard. It is equivalent to shooting out the “X” in a bulls-eye target, throwing a powder charge to within a tenth of a grain, or in our case being able to size a bullet to say .4498″ so that it fits withing .0002″ of the lands diameter (just an example, not a magic number). Precision is being able to repeat it over and over.

The accuracy question: Is your bullet properly fit to your barrel? If it is too large to load easily it is not going to work because you are the limiting factor in the load equation since your muscles and/or weight do the loading. If it is too loose it will not adequately build pressure.

The precision question: Does the bullet fit you have selected allow you to precisely load your gun? If your loading pressure goes much over 25 pounds-force you cannot control your load compression. You and I do not have force calibrated hands. If we did there would not be a need for torque wrenches, scales, or anything else that measures/limits force. I recently saw where some guy is selling a bullet seating tool for muzzle-loaders that works like a force limiter. I’m pretty sure Ultimate Firearms has had a similar tool called the Pack-Jack for some time.

There are schools of thought that tighter is better. This might be true if you  had calibrated hydraulic arms and could use the equivalent of your body weight to press home a bullet and get exactly 100% powder compression every time. The fact is that you cannot do that over and over again. It doesn’t matter whether it is your first shot every range session or your tenth and the more you shoot the less consistent you will become due to fatigue and discomfort (think about how good the end of the ramrod feels when you seat a bullet that is too tight). With bullets that are too tight you will sometimes get powder crush, some that are just barely compressed, and sometimes (worst case scenario) bullets you can’t finish pushing down the bore.

There is also such a thing as too loose. If your bullet fit is excessively loose you will not achieve ignition and you will get squib type loads. A shotgun primer will usually completely expel your bullet from the bore. A rifle primer will not. In either case always check to make sure you don’t have a bore obstruction if you have this happen to you. If bullet fit is borderline too loose you will get ignition but poor accuracy and precision on target. Sometimes a wad will allow you to straddle that line and sometimes it will not.

What you are looking for is short of difficult but somewhere a touch past really easy. I cannot tell you what the magic number is but I can tell you that the pressure needed to run the bullet down my bores for optimal accuracy and precision is somewhere around 12.5 and 23.5 pounds-force (since you will mostly likely figure this out on your bathroom scale which measures pounds-force) for optimal performance. You don’t often hear values assigned to this loading force. It is more common to hear people say things like, “one firm hand” or “two easy hands”. Those descriptions land in the 12.5 to 23.5 pounds-force range in my rifles and probably do in yours as well.

When you measure your seating force you will get a few numbers. There will likely be a peak, mid, and low number. At a minimum you will get a peak and low number. My bullets are sized so that I average about 23.5 at peak, 17.5 as mid, and 12.5 at low.  It all depends on the consistency of your bullet sizing and the quality of your barrel bore finish. My Brux peaks toward the muzzle, mid for about half the barrel, then low where it seats. My McGowen is low pressure at muzzle, peaks at a tighter spot about 1/3 of the way from the muzzle, then mid until the bullet seats. The important value is what force you must apply in the region where your bullet will contact your powder column. It cannot be difficult or you will not get consistent loading pressure on your powder column which is critical. It cannot be too easy or you won’t build adequate pressure. Seating needs to take some effort but allow you to feel your bullet make a positive stop against your powder so that you get powder compression but not powder crush.

To achieve these performance measures you have a number of ways to control bullet fit: a number of sabots, knurling tools, and bullet sizing dies. In my second blog post I posited the idea that the sabot was the weak link. It still is and if you don’t have to use them, then don’t. If you must use them you have to find the right combination that  properly supports your bullet and provides adequate but not excessively tight fit in your bore. I don’t like the idea of knurling because most guys use files but still don’t have calibrated hands although some knurl up then use a bullet sizer to draw down. Files can also fail and leave bits of steel in your bullet which then will ruin your barrel. I do not have any experience with knurling but am acquainted with guys who have ruined barrels doing it. It does seem like a viable method for increasing performance in a sabot.  The preferred method as it pertains to sabotless, and the only one we will discuss further, is to use a bullet about .001″ over your land or groove dimensions then employ either a Smooth-Form or Full-Form sizing die from Swinglock to draw it down to adequately fit your barrel.