Commercially reloaded .45 ACP 230gr plated @1200fps!

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Is it really necessary to set up that far out? I don’t see an advantage as long as your out of the muzzle blast. Also, velocity numbers that I see published aren’t generally measured at long distances and I want to be able to at least make somewhat of a comparison. That’s why I liked the MagnetoSpeed so much but unfortunately it was too limited in fitment without spending a bunch of money for attachments.
 
5 yards is plenty for a .45 for a pro chrono. That’s what I used to set mine up at. I didn’t have quite as bad as readings on .45 as you’re having though. Are you in direct sunlight? Did you try the sharpie trick at all?
 
Yes, we tried the Sharpie trick with no change in results. It was a cloudless sunny day which I’m aware isn’t the best of conditions but the Caldwell G2 is the “upside down” chronograph which, if you believe the ads, is supposed to mitigate the direct sunlight issues.
 
I agree with many here-- set up at least 15' away from the muzzle next time.
 
I can , The chrono is to close . He is getting muzzle blast readings

That is kind of like his conclusion that its the caliber of bullets though, just a guess at this point; however, even more counter intuitive, to me. Seems more like jumping to conclusions vs drawing one from the information we have. How is it that the 45 acp using a faster burning powder messes up the reading when slower burning powders in the .223 and 30-30 do not? It's not that he cannot chronograph anything, he is doing fine with .223 and 30-30, only having problems with the plated 45 bullets. That is a clue to me.

I am not discounting the guess as impossible, just doesn't sound rational that a small volume of faster burning powder would cause problems when larger volumes of slower burning powders do not, so I wouldn't conclude that without further information.

The chronograph sensing things other than the bullet is of concern, why I have speculated it could be the plating, that being one difference between the Jacketed rounds that work and the plated ones that do not and I have seen them cause issues.

If one can contain the other debris that exit the muzzle, a chronograph can be use just a few feet from the muzzle with no problems.

Like this suppressed rifle. chrononet.jpeg

Or my "Don't bother Mrs. Morris" rig.

portable bench.jpeg

If the plating is coming off the 45 acp bullets on the way down range, the distance to get correct readings may be further away than normal.


Page 5 of the manual for the OP's chronograph does state 10-15 feet or at least one full arrow length away, for them.

https://www.btibrands.com/wp-content/uploads/2016/05/1061293-BPC-G2-instructions-rev-A-PROOF.pdf
 
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The phenomenon of plated bullets coming apart and causing issues is understood by folks that use a lot of them, especially in gun games where targets are engaged at close ranges. When they come apart, they can leave a trail of debris behind that can wind up on target like this pinwheel stream of lead around the point of impact.

bulletspray.jpg

bulletspray1.jpg

That can also cause chronograph readings to become abnormal.

There can be a number of causes, often it is crimp or being pushed too fast but its also a problem for gain twist barrels, with rounds that are fine out of regular barrels.
 
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OP, another question, you mention your 9MM loads as being where they should be. What are you loading to get consistent 1200+ FPS out of a Sig 365?
OP, another question, you mention your 9MM loads as being where they should be. What are you loading to get consistent 1200+ FPS out of a Sig 365?

124gr RMR FMJRN over 4.0gr Clean Shot
25D6DE0B-3571-439E-8080-81F6A6802F49.jpeg

Same load yielded around 1230fps out of my Sig P320 but I didn’t keep the results
 
I’ve been forgetting to mention that the chronograph is almost new. The only thing I really have to compare to any of our results are two different .308 loads shot in two different rifles and both gave very similar results to what my MagnetoSpeed chronograph gave about a year ago.
 
I don’t think the plating is coming off and causing the problem. We've pretty much established that the 1200+ velocity is impossibly high and the 700-800 fps that is likely wouldn’t be nearly fast enough to scrape the plating off of a bullet that RMR sells.
My feeling is that we're setting up too close. I’m just not knowledgeable enough to speculate why the other calibers don’t seem to be affected. Even if they are affected, they’re still yielding results within what would be expected unlike the .45s.
 
I shoot Clean Shot with a 124gr coated Acme RN bullet. 4.2gr is the load I remember. I think I get about 1100fps out of a 4" barrel. Yours seems a little fast for a 4gr charge... but every chronograph and and every gun/barrel is different. I would be interested in your results when shooting, placing the chrono farther out.

The Caldwell G2 chrono is a neat unit. I hope you get this all sorted out!
 
I don’t think the plating is coming off and causing the problem... I’m just not knowledgeable enough to speculate why the other calibers don’t seem to be affected.

You might be right but there is only one way to know. I am going off the facts that you have given us. What is the one thing all of the rounds you have that are correctly read by the chronograph, have in common? They are jacketed bullets. What is one difference about the rounds you have that are acting goofy? They are plated. My knowledge of the problem illustrated above comes from shooting hundreds of thousands of plated and viewing results from many more thousands being shot by others. It is not always a problem but one that is unique with plated vs jacketed. Why my very first question was if the other rounds you had success testing were plated. Had the answer been, 'yes, all the others were plated as well.' I might have made other speculations.

I figured with your positive results in three other firearms, that you knew what distance you could shoot from and that you knew how to charge the battery in your device. So, I honed in on the one obvious difference.

Now its up to you to prove or disprove the hypothesis. I have always found the scientific method pretty good at finding solutions to problems. Make a guess and prove or disprove it, then move on. Find some jacketed 45 bullets and your answer is just a few shots away

If your bullets are coming apart they won't be the most accurate either. You might be able to move the chronograph far enough the debris don't make it there but if the load isn't accurate enough to avoid impacting your chronograph, it won't work with even the jacketed rounds at that point.
 
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OP, another question, you mention your 9MM loads as being where they should be. What are you loading to get consistent 1200+ FPS out of a Sig 365?

124gr RMR FMJRN over 4.0gr Clean Shot
View attachment 913429

Same load yielded around 1230fps out of my Sig P320 but I didn’t keep the results

I too was wondering about 1200 fps out of a Sig P365.

The Clean shot data sheet shows that with a 124 gr bullet 4.2/4.4 gr will get you around 1060 fps.

There's NO way you're getting 1200+ with four grains with a 124 gr bullet out of a Sig P365.

Something is seriously wrong with your chronograph.
 
There's NO way you're getting 1200+ with four grains with a 124 gr bullet out of a Sig P365.

Something is seriously wrong with your chronograph.

I’m definitely leaning that way myself. We’ll run all rounds through at longer distance first just to get rid of that variable and then I’ll have my friend contact Caldwell if need be.
 
Is it really necessary to set up that far out?

Its just easier for me. I have to put up a target anyway, and I can just set the chronograph in front of it. I think the only advantage would be that bullets pass through the Chrony more consistently. That and I’m not comparing my loads to yours, I’m comparing my loads to mine. I don’t think commercial chronographs are all that accurate and constant.
 
I finally got back to the range after almost two weeks. Set the chrono up at a measured 15’ to determine once and for all whether the chronograph was at fault or whether we were. I'll let the results speak for themselves......

F4476458-D29B-4A12-AB64-F18F2B66632F.jpeg

So, obviously we were set up too close. It’s hard to believe that the .45acp muzzle blast from what was likely about 8-10’ was enough to throw the results off that much. What I find even more surprising is that it didn’t throw off the results of a .308 which had been set up at the same 8-10’ distance and measured average velocity within 18fps of what a Magnetospeed V3 had given me about a year ago.
 
So, obviously we were set up too close. It’s hard to believe that the .45acp muzzle blast from what was likely about 8-10’ was enough to throw the results off that much. What I find even more surprising is that it didn’t throw off the results of a .308 which had been set up at the same 8-10’ distance and measured average velocity within 18fps of what a Magnetospeed V3 had given me about a year ago.

Makes sense. The .308 bullet probably reached the first trigger before the soundwave did, even that close. What I found odd is the consistency of the erroneous reading! :D
 
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