First .204 loads, too fast to be true?
Posted: Sat Oct 24, 2009 1:19 pm
I went to the range this a.m. with my first ever rifle reloads, 32-grain loads for my Savage 12 VL. My goal was to see how close I could get to Hornady's claimed 4225 fps and maintain the amazing accuracy this rifle had displayed with factory ammo.
I needed a couple of shots to get the chrono properly positioned and the first shot that registered (30.2 grains of BL-C(2), which was supposed to be .5 grains below max) clocked at 4207 fps. Holy moley! Not only that, I tungsten coated this batch of bullets, which I was expecting to cost me 100 fps or so. The primer was pretty flat but not cratered and the head and shoulder miked to about the same a my reference once-fired Hornady casing.
So I fired the next round, loaded 0.1 hotter, 30.3 grains. It clocked at 4219 fps and its casing inspected about the same as the 4207 fps round.
At that point I began to think I'd somehow goofed and loaded them too hot, so I grabbed the other batch, same bullet but loaded with 25.4 grains of RL-10x, 0.9 grains below its max. It clocked at 4097 fps.
At that point I was convinced they were just too fast. Either I had screwed up both batches, or my scale (RCBS Rangemaster 750) was reading too low or my chrony (Chrony Beta) was reading too high. So I closed up shop and came home.
Measuring all the spent cartridges back home, I still found nominal differences between their expansion against the expansion of the reference spent factory load cases (Hornady and R-P). Nominal=too little for me to detect repeatably with this caliper. Unfortunately, I decapped all the factory loads and didn't keep one with a spent primer intact for a reference (or fire any more today) so I don't have anything to compare them to.
This shows the primer on the 4207 fps load, next to an unfired R-P factory round:
This is a side-view of primer from the 4219 fps round:
It definitely is a bit top-hatted but I also wonder if this might be because the primer wasn't seated deep enough.
The bolt lift effort did not seem to increase. Using an RCBS dial caliper, I couldn't tell spitting difference between the expansion at the shoulder and the head of my loads versus the reference spent factory loads. None of the primers showed cratering and, honestly, I don't think I would know the difference in a well-flatted primer and an excessively flattened primer. And I'm wondering if that top-hatting was because I just failed to install the primer deeply enough.
Bottom line, unless my scale is royally screwed up (it's new and unproved but, yes, I calibrated it before every use), I don't know but what everything I'm looking at -- except those chrono velocities -- is perfectly normal. Still, those velocities are so high, and I'm so new to this, I'm concerned I've somehow goofed.
So what do you think? I plan to check my scale against a mechanical one but won't have access to it until Monday. I didn't think to chrono a factory load. If it's "faster than advertised", that might be a clue that the chrono is out of whack. So I'll do that soon -- maybe tomorrow -- and update this post.
Range and load data:
Temp: 50°F
Wind: 2G7
Baro: 29.93"
First five rounds:
Brass: Once fired Hornady
Bullet: WS2-coated 32-grain Nosler
Primer: Federal match small rifle
COL: 2.34"
Powder: BL-C(2)
Charge: 30.0, 30.1, 30.2, 30.3 & 30.4
Final round:
Brass: Once fired Remington
Bullet: WS2-coated 32-grain Nosler
Primer: Federal match small rifle
COL: 2.34"
Powder: RL-10x
Charge: 25.4
I needed a couple of shots to get the chrono properly positioned and the first shot that registered (30.2 grains of BL-C(2), which was supposed to be .5 grains below max) clocked at 4207 fps. Holy moley! Not only that, I tungsten coated this batch of bullets, which I was expecting to cost me 100 fps or so. The primer was pretty flat but not cratered and the head and shoulder miked to about the same a my reference once-fired Hornady casing.
So I fired the next round, loaded 0.1 hotter, 30.3 grains. It clocked at 4219 fps and its casing inspected about the same as the 4207 fps round.
At that point I began to think I'd somehow goofed and loaded them too hot, so I grabbed the other batch, same bullet but loaded with 25.4 grains of RL-10x, 0.9 grains below its max. It clocked at 4097 fps.
At that point I was convinced they were just too fast. Either I had screwed up both batches, or my scale (RCBS Rangemaster 750) was reading too low or my chrony (Chrony Beta) was reading too high. So I closed up shop and came home.
Measuring all the spent cartridges back home, I still found nominal differences between their expansion against the expansion of the reference spent factory load cases (Hornady and R-P). Nominal=too little for me to detect repeatably with this caliper. Unfortunately, I decapped all the factory loads and didn't keep one with a spent primer intact for a reference (or fire any more today) so I don't have anything to compare them to.
This shows the primer on the 4207 fps load, next to an unfired R-P factory round:
This is a side-view of primer from the 4219 fps round:
It definitely is a bit top-hatted but I also wonder if this might be because the primer wasn't seated deep enough.
The bolt lift effort did not seem to increase. Using an RCBS dial caliper, I couldn't tell spitting difference between the expansion at the shoulder and the head of my loads versus the reference spent factory loads. None of the primers showed cratering and, honestly, I don't think I would know the difference in a well-flatted primer and an excessively flattened primer. And I'm wondering if that top-hatting was because I just failed to install the primer deeply enough.
Bottom line, unless my scale is royally screwed up (it's new and unproved but, yes, I calibrated it before every use), I don't know but what everything I'm looking at -- except those chrono velocities -- is perfectly normal. Still, those velocities are so high, and I'm so new to this, I'm concerned I've somehow goofed.
So what do you think? I plan to check my scale against a mechanical one but won't have access to it until Monday. I didn't think to chrono a factory load. If it's "faster than advertised", that might be a clue that the chrono is out of whack. So I'll do that soon -- maybe tomorrow -- and update this post.
Range and load data:
Temp: 50°F
Wind: 2G7
Baro: 29.93"
First five rounds:
Brass: Once fired Hornady
Bullet: WS2-coated 32-grain Nosler
Primer: Federal match small rifle
COL: 2.34"
Powder: BL-C(2)
Charge: 30.0, 30.1, 30.2, 30.3 & 30.4
Final round:
Brass: Once fired Remington
Bullet: WS2-coated 32-grain Nosler
Primer: Federal match small rifle
COL: 2.34"
Powder: RL-10x
Charge: 25.4