Refining Paper-Patched Loads for Smokeless Powder

Bench Topics by Mike Fairbanks

n a recent column, I investigated the relationship between Ia bullet’s prepatched diameter and its grouping ability. After test- ing a series of bullet diameters in four different rifles, two sweet spots were identified: bullets right at or slightly larger than bore diameter and again when bullet diameter ap- proached groove diameter. Due to the difficulties associated with the groove diameter slugs, a prepatched diameter at or slightly larger than bore is recommended. A simple test of fit would be to try to slide the Test loads - note the waterproofed patches on bullets at left. naked bullet into the muzzle. If it slips in with a slight resistance, it’s that a smooth-sided slug is prefer- American Rifleman worked with the right size. In addition to coming able to a grooved bullet. paper-patched bullets in the .308 to this conclusion about prepatched If I may add my own conjecture, Winchester, .30-06 and .300 Win- bullet diameter, I also investigated I think Matthews overemphasizes chester Magnum in the interest of the factors of bullet hardness, patch the role of “grip” in the barrel but full power with cast bullets. In his type and powder choice, hoping to appropriately hints toward minimiz- March 1977 article “Paper Patched further refine smokeless powder ing bullet distortion and maximizing Bullets Come of Age,” Harrison paper-patched loads. coaxial guidance as more important. provides a few rules for the shooter At the end of Paul Matthews’s Although one of the biggest benefits using a paper patch to obtain top book The Paper Jacket, he summa- of a paper patch is its ability to ac- velocities with poured slugs: rizes his findings on what makes a curately throw bubblegum-soft lead “Cast the bullets of hardness ac- patched bullet perform and starts at velocities upwards of 2,000 fps, cording to the load – for full loads, with the suggestion that softer is the same basic parameters of fit and Bhn 16-20, or slightly softer than better. Much of this emphasis on hardness that govern conventional linotype . . .; for 2000 fps, about softness is motivated by the in- cast bullet accuracy must also be 12-14 Bhn which is softer than tended use on game, but Matthews considered when using patched bul- Lyman No. 2 metal. Hardness is not surmises that the softer the bullets. Even though it is possible to critical but must be approximately let, the greater the upset and radial achieve fine accuracy at 2,000 fps correct for best results. Very unsuit- thrust upon firing and the better the with a 5 Brinell hardness number able metal, of course, will fail. grip in the rifling. Keeping with the (BHN) bullet, there’s a good chance “Size bullets .301 inch.” (Cast theme of bullet engagement, he also these results will require extra effort Bullets, NRA Publication, pg. 97) suggests that “nothing but the paper to attain. With a slight shift in hardness, patch and its attendant lubricant During the mid-1970s, Col. the first rule could apply directly to should ever touch the barrel,” and E.H. Harrison and the staff at The any lubricated, grooved cast bullet. 1 LoadData.com Bullet strength is an important part of any cast bullet. One could look at a paper patch as a layer of “super- lube” that allows higher speeds with softer alloys than are possible with conventional groove/lube cast bullets. The fact that Harrison’s tests were performed in .30-caliber rifles and that he recommended a bullet slightly larger than bore diameter correlates exactly with my own findings in regard to prepatched bullet size. In my own tests of bullet hardness, alloys as soft and ductile as 5 BHN roof flashing and as hard as 20 stick-on patches BHN heat-treated range scrap were utilized. A 10, 15 and 20 BHN test for the .45-70 and .458 Lott (stick- work, it can also act as a lubricant perature. Careful attention was paid on patch, 0.456 inch diameter bul- between the bullet and patch and to ensure complete coverage so that lets) revealed insignificant accuracy cause the patch to slip while seating a small amount of lube was wiped gains at the harder levels but also the bullet. Clean bullets and proper off the bullet at seating. No prob- showed no drop-off in group size. loading technique are essential for lems due to the buildup of excess The graph below traces the correla- both patch types. lube occurred within the seating tion between hardness and accuracy One factor not investigated was die, no doubt due to the softness of of 304 individual groups fired from patch lubricant. Matthews’s rec- the lube and the fact that the total four different rifles. Although the ommendation of petroleum jelly amount on each bullet was pretty curve wavers, it does show a clear and yellow beeswax lube (55:45 small. trend favoring harder slugs. Despite by weight, melted and thoroughly As an aside, Matthews developed his affinity for soft bullets, Mat- mixed) was the only lubricant used a method of waterproofing and thews also states: “Usually a bullet throughout the tests. The patched toughening his patches for hunt- slightly hardened with tin will give bullet was spun on the surface of ing use, especially in leverguns, by better accuracy than one of pure solidified lube, similar to buttering soaking a heated, patched bullet in lead.” a cob of fresh corn. This was done melted beeswax, allowing it to cool with bullet and lube at room tem- and shrink overnight, and lubricat- Hardness vs. Accuracy The grouping ability of two types of patches was also investigated during these tests. A traditional-style, double-layer, moistened, wrap-on type and a single-layer, adhesive label, stick-on type were used head- to-head throughout all tests. Tracing paper measuring 0.0022 inch thick was used for the double-wrapped patches. This method of patching typically added .007 to .008 inch to the diameter of the unpatched slug. File folder labels or address labels measuring 0.0035 inch thick were used for the single-wrap patches. These patches typically added .006 to .007 inch to the diameter of the unpatched slug. Although the adhesive is what makes this type of patch

LoadData.com 2 ing and loading it as a normal patch. In my limited tests, this has proven to be an excellent method of in- creasing the robustness of a hunting slug. Be aware, however, that heat- ing and soaking a stick-on patch can denature the adhesive; therefore, the conventional dried-on patch is recommended for waterproofed patches. These waxed patches performed identically with normally lubricated patches in my limited tests, but I would recommend to those wrap-on patches who try this technique to give it a few trial runs before any serious use. The difference in the overall marily because they’re ready to load remaining in the chamber throat group size average between the two right after patching, both types have was the .375 H&H. It is surmised patches was less than 0.18 minute of useful features. Moistening and that the large cone-shaped throat angle (MOA) for over 300 groups, wrapping a patch does not require kept the patch from partially shear- so patch preference is a draw. With- much more effort than aligning, ing off the bullet. The data shows out close analysis, it is my percep- sticking, folding and compress- no particular set of circumstances tion that bullets patched with the ing a stick-on patch. The wrap-on that led to a paper ring as the rings wrap-on type behaved in a more does require a drying period and is appeared at any given diameter, regular manner as bullet diam- slightly more delicate – until after hardness, patch type and powder. eters increased, while the stick-on it’s loaded. It can also be water- Extra lubrication on the patch did type would give an excellent group proofed and therefore toughened help reduce the occurrence of paper here and an excellent group there against moisture and abuse, and I rings, but a greasy bullet does not and perform poorly in between. would choose this type for hunting carry well in a pocket. The inci- The wrap-on patches also seemed purposes. The long term interaction dence of a paper ring did not ap- to leave the bore cleaner and more between the patch lubrication and pear to harm accuracy to any great polished looking. Perhaps this can the adhesive of the stick-on type was extent, and often, especially in the be traced back to the rifling cutting not tested, but in the short term, .45-70, patches with known damage down into the adhesive and it leav- the adhesive can be problematical as performed admirably. ing some resultant residue. described above. A short test of seat- A wide range of powders were The stick-on patches remained ing depth indicated that an overall utilized to varying degrees of suc- fully intact on the bullets, even length where the patch enters the cess among the four rifles, includ- when significantly distorted at im- rifling leade approximately 0.125 ing Trail Boss, Herco, SR-4759, pact. This type of patch exemplifies inch at the full chambered position MP-5744, IMR-4198, IMR-3031, Matthews’s description of the patch as the best length. Both 0.250 inch H-4895, H-1000 and US-869. as a “paper jacket.” On the other jam fit and 0.125 inch short of the Polyester fluff as a case filler was hand, the wrap-on type consistently leade produced groups about one used in most loads with SR-4759, gave a nice blast of fine confetti at MOA larger on average. MP-5744, IMR-4198, IMR-3031 the muzzle, and no evidence of these The only rifle of the four tested and H-4895, although the two last patches clinging to the bullet was that did not evince “paper rings” powders were loaded to 100 percent found. This performance exempli- clinging to the fired case mouths or capacity in the .45-70. (Yes, I used fies Randolph Wright’s description of the patch acting more like a sabot (albeit a weak one). I did find it in- teresting that the size of the confetti flakes increased toward the end of the tests, and it is assumed to be the result of the bore taking on a fine polish and cutting the patches less. Although I was initially in favor of the stick-on type of patch, pri- Recovered bullets showing two with stick-on patches versus two with conventional patches.

3 LoadData.com fillers and take no responsibility for tion presented here. In my case, the cartridge of moderate intensity and others doing so!) These medium details don’t always sink in the first easy-on-the-bullet bore will add to burn-rate powders always performed time, so I performed some investi- the success rate. When Paul Mat- well with a filler, but patches would gations of my own. It has become thews suggests a bullet of moderate often fail when loaded over an air clear that, in many ways, top perfor- weight cast from an alloy around space. Instead of utilizing a filler mance with paper-patched bullets 7 BHN, sized to bore diameter or with the two quickest powders, they is due to many of the same factors slightly larger, patched with a dou- were settled to the rear of the case as top performance with grooved/ ble wrap of onionskin paper, lubed before firing. The loads with Herco lubricated cast bullets. Consistency with a light coating of petroleum always resulted in a prodigious air alone is not enough to ensure accu- jelly/beeswax, loaded over a charge space, while the bulkiness of Trail racy. Bullet strength and size must of IMR-3031 that allows 100 per- Boss often brought the charge to correlate to the intensity of the load cent load density in a .45-70, he’s 100 percent capacity. The two slow- and the dimensions of the barrel putting into practice the balance of est powders were always loaded to it’s fired in. A firearm set up for a these factors. 100 percent density and sparked with a magnum rifle primer. For the most part, powders performed as expected in that the pis- tol powders and the slow-burning, magnum rifle powders did not pro- duce the best performance. No mys- $39.95 tery here; they’re not designed for Plus Shipping this application! Occasionally one & Handling or the other (fast or slow) would throw a nice group, but my recom- Catalog mendation is to utilize a powder of #544 modest burn rate and load it to 100 SHIPPING & percent capacity, or use a powder HANDLING: designed and/or recommended by $7.25 U.S. the manufacturer for use in reduced Call for Foreign. loads. Therefore, I burned a lot of AZ Residents SR-4759, MP-5744 and H-4895 add to good effect, and the majority of 9.35% tax. those loads benefited from the in- clusion of a grain or two of polyester fiber filler to bring load density up to 100 percent. Even so, there is no reason to choose a .375 H&H or .458 Lott specifically for throw- ing midweight patched bullets at less Propellant Profiles, than 2,200 fps. It can be done in covering the last 45 years, is the most these rifles with reduced charges and comprehensive reference on the gunpowders fillers, but a .45-70, .444 Marlin, available to American reloaders. .38-55 or .375 Winchester or even .44 Magnum or .500 S&W carbine This updated Fifth Edition includes 452 pages would be a much better choice. Not of detailed descriptions and photographs of the only is case capacity more appropri- most popular current and discontinued powders ate with these calibers, but they are available, including recommended loads and tips. also typically found in firearms with slower twist rates and graceful throat configurations that are better for Wolfe Publishing Company patched bullets. 2180 Gulfstream, Ste. A • Prescott, AZ 86301 A careful reader of the literature TOLL FREE: (800) 899-7810 • FAX: (928) 778-5124 on paper-patched bullets will al- ORDER ONLINE: www.riflemagazine.com ready know much of the informa-

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