Solid vs Removable Pilot—Which is Best?
Both solid and removable pilots do an equally good job–assuming proper clearance with the bore—and therein lies the problem. Solid pilots are ground to one size which is usually slightly smaller than minimum industry bore size; they will fit most commercial barrels closely enough to produce good results. Because there is less work to make a solid pilot reamer, they’re also about 25% less expensive.
Removable piloted reamers are made with a journal (spindle) on the front end that allows precision bushings of varying sizes to be fitted to the reamer. The gunsmith can then select a pilot bushing that fits the bore of a particular barrel with exactly the clearance he wishes. Although the reamer with removable pilot costs more initially, and buying a selection of pilot bushings adds to the expense, this arrangement allows fine-tuning of the barrel/pilot fit.
Years ago, we used to sell about five solid pilot reamers for every one fitted with a removable pilot. This ratio has changed to approximately two solid for every one removable. Firearms tooling–other than reamers–that uses pilot bushings (indicating rods, specialized form cutters, etc.) has become more popular and it makes sense to have a selection of bushings that can be used on both a chamber reamer and another piloted cutter that will be used on the same build.
In the end, your budget and needs will decide which system is “best”.
To What Dimensions and Tolerances Do You Make your Headspace Gauges?
Rimless, shouldered gauges are available in go, no-go, and field. All other gauges are available in go and no-go only. Please refer to Headspace Gauge Dimensions and Tolerances for specific details.
How Do I Deal With Chatter?
The thought of reamer chatter during chambering strikes fear in the heart of even the most experienced gunsmith. This condition can ruin an expensive barrel and add unnecessary cost to what should have been a profitable job. With many possible causes of chatter, it’s not unusual for several to be present at one time. Please review our article Chatter on the types, causes, and cures of chatter for help troubleshooting this problem.
How Are “Improved” Chambers Headspaced?
When “improving” a standard chamber, the barrel must be set back so that fireforming may be done safely and proper chamber length achieved. Headspace gages—made with the shoulder angle of the original chamber, but .004”/.006” shorter than standard–are used to check the headspace dimension. A “light touch” should be used when checking headspace of improved chambers.
“Improved” calibers work well when done properly and can offer real performance benefits when compared to factory cartridges. Once the principles of gaging these chambers are understood, cutting improved chambers is no more complex than cutting standard chambers. Please contact us if you have any questions about the principles or processes described in our article on Ackley Gaging. It’s better to ask a question than to ruin a job.
Why Does Firing 5.56 Ammo in a 223 Rem Chamber Result in Higher-Than-Normal Pressures?
Comparing industry-standard chamber specs for the two calibers reveals that the 5.56 chamber is slightly larger in diameter than the 223 in the body and neck areas, has slightly longer headspace and, most importantly, a throat configuration both larger in diameter and longer with a more gradual lead angle into the rifling.
Remember that the 5.56×45 chamber originated in select-fire weapons, capable of sustained full-auto fire, which makes guns hot—the larger/longer chamber and more gradual lead of the 5.56 is designed to handle these conditions. Ammunition for 5.56 and 223 share the same external dimensions, but the 5.56 is loaded to higher pressures. This pressure differential can be exacerbated by firing 5.56 rounds in a smaller chamber, with shorter and steeper throat. As the gun heats up from rapid firing, pressure can increase until a host of bad things happen. Pierced primers, primers blown into the fire-control system, and stuck cases can all result.
So, to avoid over-pressure—and all the problems that come with it—don’t shoot 5.56 ammo in guns chambered for 223 Rem. 223 Rem ammo can safely be fired in guns chambered for 5.56, but keep the 5.56 out of those chambered for 223 Rem.
Why Won’t You Make 7.65 x 53 (Argentine) Headspace Gauges?
We’re occasionally asked to supply headspace gauges for checking 7.65×53 (Argentine) rifles. In these instances, we decline the request to make the gauges and this leaves our customers wondering why. Our article regarding Argentine Headspacing Information will help explain this.
High Speed Steel, Carbide and TiCN Coating
It’s a fact that cutting tools made from carbide last longer than tools made from high speed steel. Carbide can be run at higher spindle speeds, with faster cycle times; being harder than high speed steel, it lasts longer as well.
The downside of carbide is it’s more expensive, requires modern, rigid machinery and closely controlled feedrates. Unless feeds and speeds are optimized, it’s sometimes difficult to achieve satisfactory surface finishes with carbide. That said, many shops specializing in high production have found it worthwhile to invest in the machinery needed to use carbide tooling successfully.
High speed steel, on the other hand, is less expensive and won’t shatter into pieces if dropped on your shop floor. Further, it’s more forgiving of less-than-optimum feeds and speeds—a good finish is easier to produce with high speed steel.
High speed steel has distinct advantages for the individual ‘smith, as well as the low-to-medium volume manufacturer, but it would be nice if the tools could be made to last longer. This is where TiCN coating comes in.
Titanium CarboNitride (TiCN) coating is a process that infuses a very thin (.0001”-.0002”) layer of TiCN into the surface of high speed steel tools. The coating is extremely hard and “slippery”. Because of these characteristics, it offers better surface finishes and at least twice the tool life of uncoated high speed steel.
Titanium Nitride (TiN), “gold” coating, has also been used for years in this role, but isn’t as useful for cutting tools as TiCN. TiCN is a light-to-dark grey coating, sometimes with a pink tint.
We offer TiCN coating of individual reamers @ $18.00 each, with discounts available for higher volumes.
Doubling the life of a $100.00 reamer for an additional $18.00 seems a good bargain to us, but may not be appropriate if you’ll only use a reamer a few times. If, however, you cut a lot of, say, 308 Win chambers, the extra cost begins to make sense.
Let us know if you’d like your next reamer TiCN coated and we’ll be happy to oblige.