Range Report: Barnes XPB [Mission Aborted]

[Hoot]

I finally fixed the broken image links due to an ISP change several years ago

I'm a big proponent of substantial neck tension with the 450b, especially when shooting the lighter bullets with Lil Gun. Seems like the words too much and neck tension are an oxymoron when considering this caliber and lighter bullets. That was up until last Friday. Tim (wildcatter) had reported rave results using the Barnes 200 gr XPB loaded as long as the magazine allowed and having a stab crimp applied to the rearward driving band groove. Notice the term driving band as opposed to cannelure. Cannelures are intended to bite into with your crimp for additional neck tension. Driving bands and their respective grooves are intended to reduce the amount of bearing surface between the barrel and bullet.

Here the two are side by side:



In the past, several people myself included, documented the process of modifying the Lee .45-70 FCD to allow using it to produce both good mouth crimps and side stab crimps. That effort left me with one wide (original) jawed and one narrow jawed version. The narrow jawed version being more appropriate for stab crimps. Using the same Lil Gun charges I already documented in Parts I & II, but loading to catch the rear driving band groove with the stab crimp as opposed to the front with the taper crimp, I seated 8 steps of 5 rounds, ranging from 38gr to 45gr of Lil Gun. That seat used as much of the magazine as I felt comfortable with, 2.29 inches COL.

After seating, I ran all 40 cases and 2 additional experimental sets of 5 through the taper crimp set to yield .475 mouths right at the very edge of the mouth, as measured with a quality micrometer, not my less accurate caliper.



After the taper crimp, I ran all 50 through the narrow jaw, modified Lee FCD stab crimper adjusted to catch the rear driving band groove and in the case of the control groups, the rear cannelure of the Hornady 200gr FTX. That's cannelure, not driving band groove. Keep that distinction... Lo and behold and not to much surprise, as a result of the amount of plunge that the case wall makes into that driving band groove being so close to the mouth, the mouths developed a flare.



Out of concern for catching the edge when chambering as well as whether they were too wide now at the mouth to thunk, I re-ran them through the taper crimp again, with just enough crimp to take the flare off.



All being right with the world, Friday morning (I took a day's vacation to get out while it was not hot) I headed to the range in my wife's Taurus. This point marks the beginning of my "cluster-xxxx", wasted, vacation day. On Wednesday evening, my wife and I dropped my F150 at the shop to see if the front end could be aligned without replacing any of the 12 year old front suspension parts and put the key in the drop slot. Those were my instructions to her and I assumed that was what she told Bill the local repairman. During the work week, the truck sits parked due to the cost of fuel and we car-pool. I drop her at the Park-N-Ride and I drive the remainder of the 25 miles to work and back home, picking her up from the Park-N-Ride later in the afternoon. Saves us a fortune in gas. Anyway, I heard nothing from Bill Thursday as he was backed up. Friday morning, I drove up too the gate at the range and have that sucker-punch in the stomach realization that my range keys are in the truck. I drove back into town to the shop and there's a hand written note declaring that they're Closed Friday Due to Funeral. Through the bay door, I could see my truck up on a lift, locked safely away. I returned to the range and waited for some other misguided soul to drive up and let me in with them. After a half hour, I called Ray, the Pistol Range Coordinator, who lives close and asked him to come over and let me in. Of course, while he was in transit, a member showed up and let me in. While I was setting up my gear on the rifle Range, Ray drove up looking disgruntled. After everything quieted back down, I snuck the water shot jugs out of the Taurus trunk and set them up, keeping an eye on the road leading to the Rifle Range.

For clarification: Our club sits on the outskirts of the greater Minneapolis Metropolitan Area and we operate under a tight Conditional Use Permit due to folks living near the range. They're S.O.L. regarding the noise, but we have to be very safety conscious. Nothing but paper targets on the backstops in front of immense dirt berms. Being the Rifle Range Coordinator, I'm supposed to set a good example. Nuff Said...

Having already tried a load reduced in velocity to simulate 300 yards, I brought the next step up in velocity to simulate 250 yards. If you read Parts I & II, guess what? This time, not only did I get to see the water spout out of all 7 jugs, but I got to actually see the dirt puff way downrange as the bullet waived Bye-Bye to the last jug:



I stood there wishing I had packed 7 more jugs in the Taurus' trunk and brought the 200 yard simulation cartridge. Oh well, I still had a fist full of targets and a mission waiting for me that promised hours of fun waiting for the barrel to cool.

The fouling shot using my Gold Standard 225gr FTX, taper crimped over 38gr of Lil Gun. clocked through the traps at 2221fps and hit .5 high .25 right of the bull. Away we go!

I started out with 38gr of Lil Gun and the Barnes with the experimental crimp. Low by standards, but that's how i like to approach changes in what I know that works. Two shots later, I'm checking the chrony which was still in the shade and finally, I shot another fouling shot 225 FTX. Spot on. I finished the remaining two shots of 38gr and poured a cup of coffee from my thermos while the barrel cooled. The thermometer I bring every trip said it was 74 degrees in the shade with a barely detectable 2 o'clock breeze. As I sat there measuring the spent brass with their .503 case head expansion and light ejector marks, while musing over the five shot average that was 137fps faster and 210fps faster at the extreme than the last effort with only a taper crimp, I wondered how I would fare at 45gr of Lil Gun, like Tim reported having shot safely. Never mind the near 3 MOA awful group.

I had with me two experiments. One being the somewhat faster Vihtavuori N110 that I tested last year with lackluster groups despite excellent SDs, using 200gr FTX bullets and the second being 38 grains of Lil Gun and the 200 FTX but instead of seating them short and taper crimping the front cannelure, I seated the to max magazine length and crimped the rear cannelure using the same amount of stab crimp force as the Barnes 200gr ones I just shot. The N110 group had no previous load tested at 38gr of Lil Gun, so nothing to compare to. Same lackluster group.

Next, I shot the five 200 FTX with the rear cannelure stab crimp and they were faster than the previous time I shot them using front cannelure taper crimp and the resulting group was quite nice. File that away for future experiments. Case head expansion was only .5025, so I was also happy with that.

Just a footnote worth mentioning. My resized brass typically mics around .501 to start with. That how my dies came and they still have plenty of wiggle room in the Bushmaster chamber, so NBD.

So, faced with what to do, I chose to try the next step 39 gr of Lil Gun. Again, I saw an increased five shot velocity average of +153 fps with an extreme again over 200fps. Again a ho-hum 2+ MOA 100 yard group and lots of ejector and the beginning of extractor marks on the case heads along with case head expansion to .504 and strong chamber wall imprinting. The highest 39gr velocity extreme of 2595 fps, in loads that previously yielded 2435 and that with a hotter mix of powder left me a little spooked facing 40 through 45gr loads still remaining. Add to that, the temperature was about to go up to the upper 80s as the shade diminished and the sun hit zenith.





Now I'm just a mere mortal. I still have everything I was born with. Some a little worse for wear and tear, but I really like keeping it that way. Not being independently wealthy, I do not have an inexhaustible supply of new rifles and ammunition. I decided to live to fight another day. No telling what would have transpired as I progressed from 40 through 45gr, but I didn't want to find out. It really sucks having to pull down all those nice loads.



...but, they aren't going through my gun. I have no problem milking all the available safe energy from a powder's burn, but I do not want to try to proof out a series of controlled explosions.

I do not re-use powder, primers or bullets once they've been loaded as a rule. I will inspect those expensive Barnes bullets and check their diameter. If they can be re-used, I certainly will, but not if they're off enough to skew results from some future experiments.

In conclusion. It appears that the crimp strength of those deep, sharp shouldered, driving band grooves exceeds what we're accustomed to seeing from cannelures. Perhaps a less firm crimp would yield better results, but it's hard to adjust a variable Lee FCD while applying shim washers to the ram so that they crimp exactly the same pressure every time, at the top of the ram stroke and the repeatability is always a crap shoot after you knock down your setup. I'll be content as a bottom feeder and leave these strong crimps to braver souls. Hating to be wasteful and before I pull these down. If some other braveheart want's to sign a statement of indemnification, they are welcome to shoot these beauties through their gun. Pitted Bore has a bolt gun. You interested Bob?

I don't want the brass back as this style of crimp and bullet leave terribly strong scars that don't iron out.



Strike Three!

I'll be back with other experiments using these fine bullets, just not a repeat of this one. If no one wants to further the cause of knowledge at their own risk, I will pull them and if they're still usable, I will load them long, but with just a taper crimp like we do with the 250's. There is still worth in long loads. I still want to revisit N110 and 2400 is in the batter's box. Also, those 275s are chomping at the bit. They also have great promise. More Water shots to follow.

whew...

Hoot

[commander faschisto]

Hoot...there's an old adage that "if something doesn't feel right, it probably isn't". I learned all about that back in my U.S. Chair Force days---you can't pull over and fix it at 30,000 feet AGL. You did the right thing. I'm sure WC can tell you that things that don't work as planned can tell you as much, or more, as the things that do!

[pitted bore]

. . . I'll be content as a bottom feeder and leave these strong crimps to braver souls. Hating to be wasteful and before I pull these down. If some other braveheart want's to sign a statement of indemnification, they are welcome to shoot these beauties through their gun. Pitted Bore has a bolt gun. You interested Bob?

I don't want the brass back as this style of crimp and bullet leave terribly strong scars that don't iron out.

Hoot-

I'll decline your offer with the greatest respect. About 25 years ago I got into some problems shooting handloads assembled by another person. I made a personal rule not to share my own loads with anybody, nor to use loads from somebody else. If another person uses my handloads and suffers a blowup because they did something dumb (like an unnoticed bore obstruction), the person will come looking for me. ("Your handload blew up my invaluable engraved J. C. Higgins benchrest rifle and made me impotent; give me your first-born child and we'll be even.")

I'd be happy to sign a form indemnifying you and yours. But, if I do some stupid trick and blow myself into next week while using your loads, you would still have to hope that your lawyers are smarter than the lawyers my heirs might hire. It's a lot cheaper to tear down the questionable loads than to talk to an attorney even for a few minutes.

Some person must have stuck some pins into the 450B voodoo doll recently. Today I tried a series with Alliant's 410 powder behind 185s, hoping it might be the magic powder for light bullets. Instead, it did the plateau trick, with no steady increase in velocity with increasing charge. Velocity was the same at 39 grains as at 45. (A load of 45 grains is a case full.) I did not use a side/stab crimp, and will try that next. If crimping doesn't help, the powder will go to my equivalent of your "bottom right drawer", the morgue for dead bright ideas.

Thanks.
--Bob

[Siringo]

Hoot -- how much did the brass shorten with the heavy crimp?

[Hoot]

Hoot -- how much did the brass shorten with the heavy crimp?

Given the down, across, back up and out of that groove transition cost something, I pondered your exact question during the process, but having forgotten to plug my one ear, it got back out.

I'll measure some when I get home from work. Having measured the dimensions of that groove as best I could, if I were to hazard a guess, I'd speculate about .003 shorter. That brass had grown back a few thousandths since the previous loading, probably in the range of 1.691-1.697, along a bell curve, with the bulk in the 1.692-1.694 range. I know I had segregated them into groups of 5 by length to at least keep them the same within a test group, but I didn't record those lengths. The lightest loads got the shortest brass and progressed upward as the loads did the same. Two made it back up to 1.70, but I sat those two aside. Likewise a couple that stayed down at 1.687. I replaced those four oddballs with 3-fire ones measuring 1.692-1.693 from my stash. I use variable partition Plano boxes to sort my stash by number of fires and length increments of .002.

51 of my best looking 1.693-1.695 stash went to BD1 in trade for 50 trimmed, new, .284 brass for future experimentation stock. If you read this Bill, they came Saturday. You should see yours today. Bob (pitted bore), I have the short ones boxed for you, but haven't gotten to the post office due to distractions. For sure by Wednesday.

Hoot

[BD1]

Hoot, the Hornady cases were in the mail on Saturday, Thanks! I'm still waiting for the taller gas check maker to get finished before I go back to working with the cast boolits in the .450. It's been over a year now...

Looking at your photos I'm thinking that your putting significantly more pressure into your stab crimp than I do. In addition, I eased the edges of the collet on my crimp die when I narrowed it up to keep it from embossing the hard lines on the brass. I did that by knocking the collet out and then using a stone lap ball on the dremel, followed by a cratex tip, I took off just enough to lose the hard edge. After doing that all signs of the stab crimp are pretty much erased by firing and resizing. I adjusted my crimp die by making up a series of dummy rounds, crimping them, and then testing them very scientifically using an impact type puller. If two sound whacks don't move the bullet I'm thinking it's good to go.
BD

[Hoot]

Hoot, the Hornady cases were in the mail on Saturday, Thanks! I'm still waiting for the taller gas check maker to get finished before I go back to working with the cast boolits in the .450. It's been over a year now...

Looking at your photos I'm thinking that your putting significantly more pressure into your stab crimp than I do. In addition, I eased the edges of the collet on my crimp die when I narrowed it up to keep it from embossing the hard lines on the brass. I did that by knocking the collet out and then using a stone lap ball on the dremel, followed by a cratex tip, I took off just enough to lose the hard edge. After doing that all signs of the stab crimp are pretty much erased by firing and resizing. I adjusted my crimp die by making up a series of dummy rounds, crimping them, and then testing them very scientifically using an impact type puller. If two sound whacks don't move the bullet I'm thinking it's good to go.
BD

The apparent problem is not one of pressure as the same pressure was applied to the Hornady's. The depth and width of the driving grooves offers no resistance to my jaws compared to the Hornady. It's more of a matter of adjusting the amount of travel they make in retrospect. My jaw width was almost a perfect, tight fit inside those grooves when dragging the wall thickness in with it. I thought I had radiused my jaw edges enough, but apparently not enough to give a smoother pass over as the crimp clears that sharp edged canyon.

Man, it seems like you have been waiting a lifetime for those tall gas checks.

I keep about 6 cases that I mechanically iron out with the expander, then resize over and over followed by blacking with a sharpie for doing test crimps as I tweak the Lee FCD in for a given load. One of them has a slit down the side to allow me to visualize where the crimp falls in relation to where that actual cannelure or groove on the bullet inside of it occurs. It's still tedious to set up and nay impossible to hit exactly the same the next time I set up without going through the entire, painstaking process again. that's one of the reasons I don't often use the stab crimp. I spent an inordinate amount of time fiddling with it last summer, most of which I never reported on. The big hangup is trying to set it up so that the crimp occurs at precisely the end of the ram travel, as that's the only way to get the same crimp from one case to the next. At first, I tried doing it by feel and while that was easy to set up, the resulting crimps and velocities were too varied for my tastes. There is a point of diminishing return, where the SD has already tightened up, though not the groups and this was the first time I believe I actually exceeded that threshold. I'ts certainly not a load-n-go setup like the other dies. Not close to as easy as setting the FCD up for a simple mouth crimp, like I use on my shouldered calibers either.

Hoot

[Hoot]

Hoot -- how much did the brass shorten with the heavy crimp?

As best as I can determine with the bullets in them, the brass shortened between .001 and .002. Not as much as I expected to find. The two groups of fired brass are interesting also. When I'm testing loads for velocity and accuracy, I take them out of the box individually, shoot them and put them back exactly where they came from. As such, their fired lengths varied somewhat according to the velocity they achieved. The slowest ones shrunk back as far as 1.688 to no shrinkage and the fast ones like that 39gr load that went 2595 actually grew in length. That one having reached 1.699. The 38gr loads came from brass that were 1.6895-1.6914 and the 39s came from 1.6915-1.6934.

Here's an interesting Point: As I shot each one, as soon as I plucked them from the brass catcher, I measured case head growth and put them back in their spot in the box. At that point, they were still pretty hot to the touch. Now, sitting here at the air conditioned kitchen table three days later, the case head growth measurements are narrower than when I measured them hot off the press. For the 38gr load, the average growth was 1.8 mils and the 39gr loads averaged 2.6 mils. That's not cause for grave concern. Now I'm feeling like a little like a granny. No denying they flew faster by about 10% than just a taper crimp in a shorter loaded case, but perhaps I was spooked too easily. I'm not thrilled with light ejector and extractor imprinting, but they were not deep enough to start shaving. I might just pull these down, toss the brass and try again with the FCD jaw edges a little more radiused and not as deep into the grooves. I would use some of my 5-fire brass in case the crimps once again don't iron out, not new brass.

Hoot

[Siringo]

Part of my concern with the Barnes 200's is they are so short and .4505 diameter. Consider the free bore that the 450 AR's have (0.10"). I may be wrong, but I don't think BD's bolt gun has the free bore and also he is running a .451 inch barrel. Is this correct? So -- with the AR, the bullet is nearly out of the case just as the center driving band is barely engaging the rifling. IF the case is not perfectly square to the bore -- it would be easy for the gas pressure to cock the bullet to one side or another,since the free bore is around .453" diameter -- plenty of room for a .4505 bullet to bounce around if not securely in the bore. I think this is a problem with most of the short bullets. There are a lot of factors against getting these to shoot well in the Bushmaster barrel.

PS: was that picture of the bullet hole in milk jug the exit hole????

[Hoot]

Part of my concern with the Barnes 200's is they are so short and .4505 diameter. Consider the free bore that the 450 AR's have (0.10"). I may be wrong, but I don't think BD's bolt gun has the free bore and also he is running a .451 inch barrel. Is this correct? So -- with the AR, the bullet is nearly out of the case just as the center driving band is barely engaging the rifling. IF the case is not perfectly square to the bore -- it would be easy for the gas pressure to cock the bullet to one side or another,since the free bore is around .453" diameter -- plenty of room for a .4505 bullet to bounce around if not securely in the bore. I think this is a problem with most of the short bullets. There are a lot of factors against getting these to shoot well in the Bushmaster barrel.

PS: was that picture of the bullet hole in milk jug the exit hole????

It's the exit hole.

For the batch I have, the segment from the rearward groove to the heel is .451 and the rest of the bullet forward of the rearward groove is .4505 inches.

In my particular rifle, the COL to the lands is 2.41 inches, so yes your concern is a valid one as that only leaves something like .11 inches of bullet in the case at that point and with the lip of the heel being radiused, it's barely under the control of the brass when it makes it to the lands. I mean barely. Even though the length of the FTX 200 is almost the same, it has a shorter distance from the tip to where it makes caliber. I can only imagine what the 160s are like.

I don't have a bullet run-out gauge to see how well they align inside the brass, but if your crimping setup isn't aligned just so-so, the stab crimp could forcibly pull it out of true and hold it there firmly, until it is fired. Historically, my best accuracy came from the taper crimp only. Unfortunately that is not coincident with maximum powder burn and consistent velocities.

Hoot