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Post by buckeye68 on Dec 21, 2023 22:39:39 GMT -5
Mark thats is some very extensive testing that you have done. Thank you for running these tests. Everyone that uses this message board can benefit from information that you have provided. We look forward to seeing you at the Polar bear shoot in Feb. Thanks, I’ll be bring Loud Mouth 2.0 with me to the Polar Bear shoot. I’m hoping you’ll bring some warm weather with you this time!
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Post by buckeye68 on Dec 21, 2023 22:55:55 GMT -5
buckeye68 What would you attribute to the reason why the 17” section produced higher velocity than the 20” section with all other variables staying the same?🤔 Was the chronograph kept in the same spot in relation to the rifle for all shots taken? How do you like that Garmin unit, by the way? Good question. Maybe it’s a node thing? I was a little surprised after I got home and started looking at the data. The Garmin was in the same place for each session. The Garmin performed flawlessly and never missed a shot. As you can see in the picture there was no scope on the gun and down range there was no target. The Garmin is super easy to use. Just point it in the right direction and hit a few buttons and it’s ready. Easy to navigate and I never looked at the directions other than to scan the QR code for the app.
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Post by gd357 on Dec 21, 2023 23:14:53 GMT -5
Mark,
Innovative thought process and test. I was kinda wondering about a couple of alternative variables, but of course the guys on here picked up on them well before I saw this. I'm sure your shoulder is worse for the abuse. It seems that the break-action smokeless guns are pretty efficient. Would it be worth the effort to add weight to the forearm/stock to try to mitigate recoil? I've done this on other rifles, but haven't looked hard enough at my CVA to come up with options. I know the factory conversion is bad enough with 65 grains of 4198. The muzzle brake helps on the stainless model.
gd
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Post by Richard on Dec 21, 2023 23:14:55 GMT -5
Thanks for doing such an extensive test! Now we know! Before we just guessed!
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Post by buckeye68 on Dec 21, 2023 23:46:08 GMT -5
Added a SilencerCo ASR muzzle break. It didn’t take much open up the break to added a Hanks Precision Gun Parts loading funnel.
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Post by buckeye68 on Dec 21, 2023 23:47:31 GMT -5
Thanks for doing such an extensive test! Now we know! Before we just guessed! Your welcome!
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Post by buckeye68 on Dec 21, 2023 23:51:55 GMT -5
Mark, Innovative thought process and test. I was kinda wondering about a couple of alternative variables, but of course the guys on here picked up on them well before I saw this. I'm sure your shoulder is worse for the abuse. It seems that the break-action smokeless guns are pretty efficient. Would it be worth the effort to add weight to the forearm/stock to try to mitigate recoil? I've done this on other rifles, but haven't looked hard enough at my CVA to come up with options. I know the factory conversion is bad enough with 65 grains of 4198. The muzzle brake helps on the stainless model. gd Unfortunately, the idea with cutting off 8” of the barrel is to make light weight, easy carry woods gun. With Loud Mouth it worked wonderful carrying in the brush. This build is coming a completely different direction. I’ll be added length to it shortly.
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Post by ballistic on Dec 22, 2023 11:45:52 GMT -5
Just my 2 cents as a reason the shorter barrel speeds increased and it goes along with what mark has said about the barrels being tighter at the muzzle end. If you’re pushing your bullet through a tight spot in a barrel - you effectively have just reduced the size of that bullet- even if by the smallest margin.
Now it’s looser when it seats against the powder.
Maybe when you hit 17” the tight spot in the barrel was gone. So your bullet was actually the tiniest bit bigger sitting next to the powder vs the others. A millisecond of extra resistance when igniting powder can give large pressure gains. That would make sense to me. Any thoughts ?
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Post by dennis on Dec 22, 2023 15:30:32 GMT -5
Looking forward to your next testing results 👍
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Post by buckeye68 on Dec 22, 2023 21:01:33 GMT -5
Plus I hate to be a pain, at 17 could you also shoot 60 and 65 gr of 4198 to see velocity. Basicly finding out amount of powder burned thru velocity.. Just added 60 and 65 grains to the original post.
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Post by buckeye68 on Dec 22, 2023 21:11:18 GMT -5
Just my 2 cents as a reason the shorter barrel speeds increased and it goes along with what mark has said about the barrels being tighter at the muzzle end. If you’re pushing your bullet through a tight spot in a barrel - you effectively have just reduced the size of that bullet- even if by the smallest margin. Now it’s looser when it seats against the powder. Maybe when you hit 17” the tight spot in the barrel was gone. So your bullet was actually the tiniest bit bigger sitting next to the powder vs the others. A millisecond of extra resistance when igniting powder can give large pressure gains. That would make sense to me. Any thoughts ? Definitely, this is what I’ve been thinking. Tomorrow I’m going to clean the 17” barrel and compare it to a new 25” barrel with my bore scope. From what I could see when I was cutting 1” pieces off the barrel is the black coating that’s on the outside of the barrel is also on the inside of the barrel. I’m just thinking out loud here but maybe the black coat is heavier towards the muzzle end of the barrel and when I got to the 17” mark the majority of the coating is gone???
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Post by buckeye68 on Dec 22, 2023 23:03:43 GMT -5
I will say the break is a major improvement ! Not sure why anyone would want to shoot one without a break.
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Post by smokelessk on Dec 23, 2023 4:46:07 GMT -5
Just my 2 cents as a reason the shorter barrel speeds increased and it goes along with what mark has said about the barrels being tighter at the muzzle end. If you’re pushing your bullet through a tight spot in a barrel - you effectively have just reduced the size of that bullet- even if by the smallest margin. Now it’s looser when it seats against the powder. Maybe when you hit 17” the tight spot in the barrel was gone. So your bullet was actually the tiniest bit bigger sitting next to the powder vs the others. A millisecond of extra resistance when igniting powder can give large pressure gains. That would make sense to me. Any thoughts ? Definitely, this is what I’ve been thinking. Tomorrow I’m going to clean the 17” barrel and compare it to a new 25” barrel with my bore scope. From what I could see when I was cutting 1” pieces off the barrel is the black coating that’s on the outside of the barrel is also on the inside of the barrel. I’m just thinking out loud here but maybe the black coat is heavier towards the muzzle end of the barrel and when I got to the 17” mark the majority of the coating is gone??? Hence the choke in a CVA barrel! All along I have read about so many CVA barrels needing to be lapped to remove the choke. It seems like CVA could totally avoid the issue by plugging their barrels before coating them. It appears your testing has uncovered a flaw in their manufacturing process, in addition to the useful velocity data you so willing collected!
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Post by Deputy819 on Dec 23, 2023 13:27:55 GMT -5
Yeah, but Mark didn’t you say that the “choke” (as far as you were aware) was only in the stainless models?🤔 smokelesskballisticGuys, Mark and I have been discussing this outside of the forum. 😁
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Post by buckeye68 on Dec 23, 2023 18:42:40 GMT -5
You are correct, I did say the SS are notorious for being choked. I believe that I found the true root cause of why the 17” barrel produced more FPS than the 20’ length did. Today I pulled out my Tess Long Bore scope and started checking all my barrel drops. The 1st drop was 24”-25” barrel drop with the crown. As you can see the same black coating that on the outside of the barrel is on the inside as well. The second problem is burrs on the inside of the barrel. This is why said lapping isn’t going to help this barrel. The only way to fix this barrel is to cut .250” off the end and start off with a square barrel and then add a nice crown. This picture shows the black coating inside the barrel. The next two picture show the damage to the crown. My last barrel drop shows there is no black coating on it. Everything matters when I comes to bullet to barrel fit. Even .0005” matters. This finding demonstrates how a bullet will slow down as it get tighter in the barrel. Also, this will raise the pressure inside the barrel.
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Post by dennis on Dec 23, 2023 18:53:41 GMT -5
You are correct, I did say the SS are notorious for being choked. I believe that I found the true root cause of why the 17” barrel produced more FPS than the 20’ length did. Today I pulled out my Tess Long Bore scope and started checking all my barrel drops. The 1st drop was 24”-25” barrel drop with the crown. As you can see the same black coating that on the outside of the barrel is on the inside as well. The second problem is burrs on the inside of the barrel. This is why said lapping isn’t going to help this barrel. The only way to fix this barrel is to cut .250” off the end and start off with a square barrel and then add a nice crown. This picture shows the black coating inside the barrel. The next two picture show the damage to the crown. My last barrel drop shows there is no black coating on it. Ever thing matter when I comes to bullet to barrel fit. Even .0005” matters. This finding demonstrates how a bullet will slow down as it get tighter in the barrel. Also, this will raise the pressure inside the barrel. Very good pics and defining the problem at the crown. My guess is that the damaged crown was the most of the initial inconsistency. Good info 👍
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Post by buckeye68 on Dec 23, 2023 21:46:57 GMT -5
Plus I hate to be a pain, at 17 could you also shoot 60 and 65 gr of 4198 to see velocity. Basicly finding out amount of powder burned thru velocity.. I through on a scope and shot some groups. 60 grains of IMR 4198 65 grains of IMR 4198
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Post by smokelessk on Dec 24, 2023 4:07:16 GMT -5
Yeah, but Mark didn’t you say that the “choke” (as far as you were aware) was only in the stainless models?🤔 smokelesskballisticGuys, Mark and I have been discussing this outside of the forum. 😁 Clearly I should read more before thinking... Haha. Of course reading minds is a little bit difficult compared to reading posts. Perhaps I should also get a little more sleep as well.
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Post by smokelessk on Dec 24, 2023 5:26:37 GMT -5
There's one thing for certain. The more you inspect and dig into CVA barrels you'll know how to build one better than CVA!
Perhaps with the muzzle device you intended for this build the name "Cottonmouth" would be a better fit. It'll be a little more like a "cough" when compared to the prior shorty you carry. But it'll still have a powerful bite.
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sqezer
Junior Member
Posts: 83
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Post by sqezer on Dec 24, 2023 7:23:41 GMT -5
There's one thing for certain. The more you inspect and dig into CVA barrels you'll know how to build one better than CVA! Perhaps with the muzzle device you intended for this build the name "Cottonmouth" would be a better fit. It'll be a little more like a "cough" when compared to the prior shorty you carry. But it'll still have a powerful bite. All I can say about my CVA 45-70 Hankins conversion, it's the same diameter from one end to the other. I did lap the barrel breech to muzzle as I do with every gun I own. Hopefully my son's will be the same.
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