17 HMR "Match" Velocities
The Bullberry 17 HMR "Match" has now been on the market for a few years and is a well proven cartridge in both performance and accuracy.
It took three reamers to finally land on what Bullberry considers optimum accuracy, however. Initially we had our reamer made
to Hornady specifications but were not happy with the results. The
chambers were – by Bullberry standards – far oversized.
A subsequent batch of about 8 barrels were chambered .002" smaller in
diameter. Now, with our final reamer dimensions, our chambers are nearly .004" smaller
in diameter than the original. This is giving us the accuracy we are always looking to achieve, without having a ruptured case problem as was predicted
by Hornady early on, by shrinking the dimensions to just accept the ammo.
Our test gun in the photo features the 3rd generation chamber dimensions as referenced above.
Velocity tests were conducted on this 11" barrel, as well as on a full length test barrel, both using Hornady's 17 grain bullet. Below is the chart based on this barrel. All velocity tests were conducted using a 5 shot group.
Note: The average velocity of this 11 inch barrel is only 132 FPS slower than the 22" carbine barrel (data shown below).
11 inch barrel
|Shot 1||2358 fps|
|Shot 2||2332 fps|
|Shot 3||2336 fps|
|Shot 4||2349 fps|
|Shot 5||2313 fps|
About the accuracy in the pistol; Fred previously put 200 rounds through the gun to make certain we did not have a pressure related problem.
Groups #1 and #2 were shot with about a 5mph crosswind, left to right, in a rather intermittent manner. Then, unusual for our area, the wind went dead calm for groups #3 and #4. Group #5 had an increasing breeze that was moving toward the target that caused the vertical lift on the last two shots, as Fred had his target box on an upslope of a sand dune.
Needless to say, he was and is happy with these results. He feels its a half inch shooter in calm conditions. Group #3, that is okay at .438", had him excited. First four shots into one hole that measures .178". Then of course, he pulled one out with a quarter inch gap. There will be those of you out there that will shoot one hole groups.
All of these were shot at 103 yards from a solid bench, off the rest you see in the top photo. This system allowed Fred to have the crosshairs of his 6.5 x 20 Leupold rifle scope dead still on target. The pistol was also tested with a 3" wide target forearm. The rest is constructed to allow vertical adjustment of sight picture by simply pulling or pushing the grip forward and back on the "incline" of the rest. Pretty good system.
Full Length Test Barrel
The below tests were performed April 20, 2002 in the Bullberry Test Pit using a Dr. Oehler Sky Screen Chronograph Model 33 with Sky Screen III system. The first screen was set 6 feet in front of muzzle. Screens are spaced EXACTLY 10 feet apart. The test began with a new production 17 HMR "Match" Bullberry bull barrel 22" long. The purpose was to determine velocities at this length, and every inch shorter down to the practical minimum length of 10". After each group of 5 shots, we cut the barrel by one inch, recrowned it, and repeated the velocity test until we had reached our 10" pistol.
Fred had predicted higher velocities than were being reported at the time from Ruger and Marlin rifles, based on our tighter chamber tolerances. While this did not occur, it did prove his other theory that we would possibly see a maximum velocity in the 17- or 18-inch range. You will see in the performance breakdowns below that the maximum velocity was actually achieved in our 19-inch barrel test.
The HUGE surprise was in the short pistols having velocities so near the carbine length barrel. Our early accuracy test barrel in stainless shot only 132 fps slower than the original 22" blued chrome-moly carbine barrel. When we finished the test at the 10" length, we found the chrome-moly barrel to be only 241 fps slower than the 22-inch length.
|Shot 1||2517 fps||Shot 1||2560 fps|
|Shot 2||2472 fps||Shot 2||2494 fps|
|Shot 3||2508 fps||Shot 3||2494 fps|
|Shot 4||2515 fps||Shot 4||2522 fps|
|Shot 5||2575 fps||Shot 5||2543 fps|
|Average||2517 fps||Average||2523 fps|
|Spread||103 fps||Spread||66 fps|
|Shot 1||2570 fps||Shot 1||2548 fps|
|Shot 2||2484 fps||Shot 2||2520 fps|
|Shot 3||2500 fps||Shot 3||2491 fps|
|Shot 4||2500 fps||Shot 4||2557 fps|
|Shot 5||2522 fps||Shot 5||2574 fps|
|Average||2515 fps||Average||2538 fps|
|Spread||86 fps||Spread||83 fps|
|Shot 1||2538 fps||Shot 1||2524 fps|
|Shot 2||2507 fps||Shot 2||2483 fps|
|Shot 3||2525 fps||Shot 3||2495 fps|
|Shot 4||2542 fps||Shot 4||2498 fps|
|Shot 5||2501 fps||Shot 5||2526 fps|
|Average||2522 fps||Average||2505 fps|
|Spread||41 fps||Spread||43 fps|
|Shot 1||2526 fps||Shot 1||2473 fps|
|Shot 2||2474 fps||Shot 2||2464 fps|
|Shot 3||2486 fps||Shot 3||2490 fps|
|Shot 4||2504 fps||Shot 4||2491 fps|
|Shot 5||2473 fps||Shot 5||2469 fps|
|Average||2492 fps||Average||2477 fps|
|Spread||53 fps||Spread||27 fps|
|Shot 1||2446 fps||Shot 1||2431 fps|
|Shot 2||2398 fps||Shot 2||2427 fps|
|Shot 3||2427 fps||Shot 3||2431 fps|
|Shot 4||2468 fps||Shot 4||2399 fps|
|Shot 5||2423 fps||Shot 5||2406 fps|
|Average||2432 fps||Average||2419 fps|
|Spread||70 fps||Spread||32 fps|
|Shot 1||2394 fps||Shot 1||2358 fps|
|Shot 2||2391 fps||Shot 2||2332 fps|
|Shot 3||2359 fps||Shot 3||2336 fps|
|Shot 4||2423 fps||Shot 4||2349 fps|
|Shot 5||2366 fps||Shot 5||2313 fps|
|Average||2387 fps||Average||2338 fps|
|Spread||57 fps||Spread||45 fps|
|Shot 1||2273 fps|
|Shot 2||2256 fps|
|Shot 3||2301 fps|
|Shot 4||2282 fps|
|Shot 5||2268 fps|
Summary: This 10" barrel produced a velocity average of only 241 fps slower than the 22" length, and only 262 fps less than the best average of the 19" length.
All 5-shot groups were shot after a damp patch of Eezox was pushed through the bore. This was done to clean out any metal particles from the cutting operation and to assure a clean bore for each group.