3200 fps with 160s: Need for Speed Part C

[pitted bore]

Post #1

A summary of what's below: Enforcer powder can take the 160-grain Barnes GAP bullet to 3200+ fps. I shot into water jugs and some newsprint at that velocity. A lot of words follow; just skip to the pictures if you want.

Warning: The loads described here did not blow up me or my rifle, but they might blow up you or yours. Or they might not. I'm pretty sure I'm working above SAAMI specs with these loads, but I'm not sure. (Translation = I probably don't know what I'm doing.)

The rifle I used in these tests was the M70 bolt rifle with a 26" bbl described on the forum previously. I'm glad it's heavy, because 160 grains at 3200 is at the upper end of the range of 300 Weatherby Mag loads.

Background: Powder selection for making light bullets go fast in the 450B is tricky. As I've stated here before, with 296, Lil'Gun, and 2400, I've run out of case volume before running into signs of excess pressure with the 160-grainers. I don't know about Blue Dot yet. Two years ago in Chap 4 of the 185-grain saga, I listed V-V N105, Ramshot Enforcer, V-V N110, and Accurate No.9 as other possibilities. A few months ago I got some Enforcer, and finally got around to trying it out last week and this. Enforcer is strange-looking stuff, made of very uniform spheres, like little tiny BBs.

To reduce the expense of working with the Barnes 160s, I started with some less costly .451 diameter, 185-grain bullets. Using CCI 41 small-rifle mag primers, I started at 35 grains and worked up at one grain increments. At 50 grains I obtained a bit more than 3000 fps.

I switched to the 160-grain Barnes GAP bullets and loaded them with a side crimp. With a trial of single rounds, these were the 9-foot instrumental velocities I recorded:
50.5 gr - - 3121 fps
51.0 gr - - 3125 fps
51.5 gr - - 3138 fps
52.0 gr - - 3145 fps
52.5 gr - - 3219 fps

I mentioned these results in Hoot's thread on the Barnes XPB when I asked about the water-jug technique for recovering expanded bullets.
Stealthshooter requested a picture of a side crimp, so the image below shows a side-crimped round. The crimp did not make much of an impression because of the solid-copper bullet, and just shows as a line on the case.

(On my web browsers, a left-click on an attached image gets rid of the scroll bars.)

[pitted bore]

Post #2

To test accuracy and to run the expansion trials, I loaded 15 rounds with 51.0 grains of Enforcer and the Barnes 160s, again with #41 primers and a side crimp. COAL was 1.116".

At the range the chronograph was at 10 feet, and the target at 100 yards. The first five shots went 3191, 3124, 3213, 3190, 3209, for an average of 3192. The second set of five: 3224, 3188, 3147, 3201, 3205, for an average of 3193. The variability is pretty high. I don't think it's necessarily my reloading techniques. Immediately after this, I put 5 shots with a 218 Bee over the chronograph that had a spread of 10 fps. The variability may be part of the system, or more Iikely I'm just ignorant about how to get rid of it.)

Without one flyer (I think I flinched?), the first four shots went into 1 inch. After a sight adjustment, the next five were about 1-1/2 inches. These sizes aren't the bragging kind, but I'm still learning.

Here are the two groups:

[pitted bore]

Recovered bullets

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Recovered bullets

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Post #3

I set up a line of seven 1-gallon milk jugs, and duct-taped them to a steel support that the handgunners at the range use to hold their falling plates. (I had the range to myself.) From 20 feet back, I got a few splashes at the shot. The slug was recovered from the third jug.

The recovered slug was mushroomed clear to the bottom of the original deep hollow cavity; see the image above. It weighed 122.4 grains, which is about 77 percent of the original 160-grains. (The bullets from the box were all within a few tenths of a grain of 160 grains.)

I fired another bullet into a tight pack of dry newspaper, which is supposed to affect the bullet like hitting heavy resistance like bone. The bullet penetrated about 7 inches into the pack, and was recovered completely mushroomed , with petals folded back. The small tips of five of the six petals were picked out of the confetti; the sixth petal retained its tip. The recovered bullet weighed 146.0 grains, or 91 percent of original weight. In the photo above it's possible to see three triangular impressions on the bullet base where the petal tips wrapped around and impacted the base before breaking off.

My interpretation (yours may differ): The bullet is designed for rapid expansion at pistol muzzle velocities of less than 1000 fps; here it's being run at more than three times the designed speed. Not surprisingly, it expands extremely rapidly. Although the bullet is very tough, it doesn't penetrate well, which is sort of an anomaly. Usually one thinks of tough bullets as being good penetrators.

[Texas Sheepdawg]

So this would be a good defense round where you don't want penetration. Boy, I wished the guys with the pressure testing gear would sign up and test some of your loads.

[BD1]

Quick load puts this load around 70,000 psi

BD

[pitted bore]

Quick load puts this load around 70,000 psi

The warning at the head of the thread is worth repeating:

"Warning: The loads described here did not blow up me or my rifle, but they might blow up you or yours. Or they might not. I'm pretty sure I'm working above SAAMI specs with these loads, but I'm not sure. (Translation = I probably don't know what I'm doing.)"

Thanks.

--Bob

[wildcatter]

Quick load puts this load around 70,000 psi

BD

BD, Try as I may, I can't really get QL to accurately pridict the pressures. Case in point, if the doc were actually at 70k psi, he'd be seeing drastic case disruptions, blown primers, broken case heads, melted brass, etc., but he has stated that he is seeing no untoward ill effects.

I even adjust the SHOT START Pressure to zero, to no avail. I am regularly seeing QL predicting pressures that are 20-40k higher than actual pressure measurements, that is for our 450b, anyways. QL does many other things I need, but pressure predicting isn't one of them.

I use Real-World Pressure equipment, but I'd like QL to work better, for the fast start, work-up's.

What recommendations do you have for my conundrum? Hoot? Anyone?..

..t

[wildcatter]

DOC, did you record any groups at those speeds?..

..t

[pitted bore]

DOC, did you record any groups at those speeds?..

..t

T-
Ya, I did, but only two. See Post #2 in this thread, which has a photo of the groups. First group was 4 shots in an inch, with a probable flinch tossing the 5th bullet off the paper. Second group was 5 shots in 1-1/2 inches. I was recording velocity at the same time.

The info is pretty well hidden in all the words.

--Bob