Re: Velocity Loss with Semi-auto vs Bolt action

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YankeeTarheel wrote: Sun Jan 12, 2020 12:26 pm One should get one of those devices that measures muzzle speed and try. I'm guessing recoil energy can either go into the semi-auto mechanism, or into your shoulder. And I'm not sure the difference between 3,500 fps and 3,470 fps is significant.
Well to many people 30fps could be a game changer. I think the energy of the bolt being blown back might take some velocity away from the bullet. Others say the bullet is already out the end of the barrel and makes zero difference. In a long range shot the target may have moved, 30 ft even ten ft could make it a miss rather than a hit. On paper prolly means nothing. However you also have to take into account that velocity means longer range, less drop.
I'm hardly an expert on this is why I'm asking. Surely there is some mathematical genius here that knows this.
“The only thing necessary for the triumph of evil is for good men to do nothing,”

Re: Velocity Loss with Semi-auto vs Bolt action

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Golly, Marlene will love this question.

From me, some thoughts as an aspiring handloader: We convert some energy from the shot to work the action on a semi automatic rifle. The rifle will be designed to work certain ammo, that is, grain weight, velocity, for a given twist. Not so in a bolt action, which converts probably nearly all of its energy to pushing the bullet. Now, I have semi and bolt. I load differently for each because of these differences. As I understand it, we can alter semi autos via gas ports and recoil springs to be able to use different ammo from the design spec. Bolts will take everything from a squibb to blowing the barrel up. If there's enough to push it out the barrel but not enough to blow it up, a bolt action will take it. I think semi's are the snotty bitches of rifles. Of course I have some--feature not a bug.

A good experiment to see if semi's eat up energy is to shoot the same ammo in a semi and a bolt and measure velocity--ten rounds of each.

CDFingers
Crazy cat peekin' through a lace bandana
like a one-eyed Cheshire, like a diamond-eyed Jack

Re: Velocity Loss with Semi-auto vs Bolt action

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Short answer: it doesn’t make enough difference to matter.

Long answer: gas operated guns might reduce velocity very slightly by tapping off a small quantity of pressure, but the difference is less than the normal potential for variation of velocity from one individual rifle to another. Recoil operated guns don’t take energy that would have propelled the bullet faster.

Differences in exact bore and chamber dimensions between military specs (loose) and the way target guns are built (tight) can cause more than 30fps difference with the same ammo.

This discussion also assumes that barrel lengths are the same, which they rarely are.
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Re: Velocity Loss with Semi-auto vs Bolt action

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tonguengroover wrote: Sun Jan 12, 2020 7:37 pm
YankeeTarheel wrote: Sun Jan 12, 2020 12:26 pm One should get one of those devices that measures muzzle speed and try. I'm guessing recoil energy can either go into the semi-auto mechanism, or into your shoulder. And I'm not sure the difference between 3,500 fps and 3,470 fps is significant.
Well to many people 30fps could be a game changer. I think the energy of the bolt being blown back might take some velocity away from the bullet. Others say the bullet is already out the end of the barrel and makes zero difference. In a long range shot the target may have moved, 30 ft even ten ft could make it a miss rather than a hit. On paper prolly means nothing. However you also have to take into account that velocity means longer range, less drop.
I'm hardly an expert on this is why I'm asking. Surely there is some mathematical genius here that knows this.
30fps can be normal variation between rounds. That is insignificant from a rifle. No one would notice it or call it a game changer unless it is a massive caliber in a short, short barrel.
It is an unfortunate human failing that a full pocketbook often groans more loudly than an empty stomach.

- Franklin D. Roosevelt

Re: Velocity Loss with Semi-auto vs Bolt action

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I do like to try long range shooting, but I do not own any precision type rifle however it is fun to do. And seems precision shooters and snipers prefer the bolt mostly. Although not specifically about the loss of velocity, it is and always mentioned.

So here's the sites I was reading about the topic.

https://sofrep.com/news/snipers-choice- ... on-rifles/

http://www.gtitraining.org/news-516-sem ... -rifle.htm

This last one has some excellent posts, mainly near the end of the thread which is barely two pages long, and old like '07
https://www.thehighroad.org/index.php?t ... un.379393/
“The only thing necessary for the triumph of evil is for good men to do nothing,”

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