Reloading velocity issue: I can't figure that one out!!!

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Originally Posted by Big Jack

Hey Fox not with a slower burn powder. Seems like a lot I know but short barrels like certain powders....

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A 22" barrel is a short barrel now? I know that longer barrels allow for a more complete burn of the powder but only to a point, even with a magnum powder. If that powder is listed for the bullet weight it should burn that powder easily within the first 18in of barrel length. I guess I am finding it really hard to believe that the 2" will give you a loss of 800fps, 80 sure but 800 seems like there is a pressure loss, either the way the bullet engages in the rifling (too narrow or too short), too far off the lands (too short) or something weird is going on with the pressure.

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Originally Posted by seabast

Question to you Jack: Can you really crimp if there is no crimp groove? I light crimp I assume?

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There are factory crimp dies, they do not require a cannelure in the bullet, they do not roll the case mouth but squeeze in.

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Originally Posted by Fox

There are factory crimp dies, they do not require a cannelure in the bullet, they do not roll the case mouth but squeeze in.

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This is the one I have.

There is already a tight fit between the bullet and the neck so how can it crimp without a groove? Won't/Shouldn't deform the bullet.

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Originally Posted by seabast

This is the one I have.

There is already a tight fit between the bullet and the neck so how can it crimp without a groove? Won't/Shouldn't deform the bullet.

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Read up in the die from Lee, the crimp will not wreck the bullet. That being said, if your gun is a bolt action and your neck tension is good then crimping vs not crimping may not do anything for you, it may actually hurt. There are tons of arguments about this online, I do not crimp unless it is a tube mag. My 222 I loaded to COAL on the load data and was not a fan, the next round I loaded out to fit the magazine and make sure I had 2 x the bullet diameter inside the case neck and you need a decent amount of force with a kinetic puller to remove the bullets.

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Originally Posted by Fox

A 22" barrel is a short barrel now? I know that longer barrels allow for a more complete burn of the powder but only to a point, even with a magnum powder. If that powder is listed for the bullet weight it should burn that powder easily within the first 18in of barrel length. I guess I am finding it really hard to believe that the 2" will give you a loss of 800fps, 80 sure but 800 seems like there is a pressure loss, either the way the bullet engages in the rifling (too narrow or too short), too far off the lands (too short) or something weird is going on with the pressure.

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So, how do you explain that using two faster burning powders gave me a MV close to the reloading data? Same primer, case, rifle, OACL, setup and chrono....
Sometime , it's good to just keep his mind open, listen to others and try different things. :)

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Originally Posted by Fox

Read up in the die from Lee, the crimp will not wreck the bullet. That being said, if your gun is a bolt action and your neck tension is good then crimping vs not crimping may not do anything for you, it may actually hurt. There are tons of arguments about this online, I do not crimp unless it is a tube mag. My 222 I loaded to COAL on the load data and was not a fan, the next round I loaded out to fit the magazine and make sure I had 2 x the bullet diameter inside the case neck and you need a decent amount of force with a kinetic puller to remove the bullets.

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I checked that a while ago and I ended knowing less than before..... Internet can make matter worse sometime....

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Originally Posted by seabast

I checked that a while ago and I ended knowing less than before..... Internet can make matter worse sometime....

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It depends on your gun and your setup, 3 rounds in 1 ragged hole at 100 yards with my 222 Rem tells me that I do not need to crimp anything to have it shoot right, your gun may not be the same but there is not really any hard and fast rule about one being better than the other. If you think about it, if you have a crimp die that will crush the neck down to a specific diameter and your neck of your brass is not uniform in thickness then you will have a different pressure applied to holding in the bullet with 2 different loads. If you just use the expanding ball on the sizing die and the diameter of the bullet then you are sizing on the inside and installing your bullet on the inside, which should be more accurate for pressure holding the bullet in the case neck. Now, if your bullets are not uniform in diameter this goes out the window. If your case necks are uniform (good brass or turned) and your bullets are mint then crimping can bump up your pressure making the body of the case a stronger pressure vessel which will cause the uniform bullet in a uniform case neck to leave the case neck at a uniform pressure and therefore have a uniform velocity with a uniform and slightly longer burn time (slower burning powder stretched out a bit).

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Originally Posted by seabast

So, how do you explain that using two faster burning powders gave me a MV close to the reloading data? Same primer, case, rifle, OACL, setup and chrono....
Sometime , it's good to just keep his mind open, listen to others and try different things. :)

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It is not that I do not have an open mind, it is that I find it really hard to believe that 2in of barrel length will have a 30% drop in velocity.

Here is a link to a test that was done with a 308 Win.

http://bulletin.accurateshooter.com/...barrel-length/

What I am saying is that if your powder is matched to the bullet (using published data) then losing that much over 2in does not seem to click based on a lot of testing. If you are running a significantly shorter barrel like a 16in trapper 30-30, do not expect to get the same velocity of a 24in barrelled rifle but you should also not have a 30% loss in a couple inches.

Good link Fox...I see they have one for the .223 as well with basically the same loss (22-30 ft/sec) per inch.

Basically a 7% differance in of velocity between a 26" barrel and a 16.5 " barrel....

http://bulletin.accurateshooter.com/...velocity-test/

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Originally Posted by MikePal

Good link Fox...I see they have one for the .223 as well with basically the same loss (22-30 ft/sec) per inch.

Basically a 7% differance in of velocity between a 26" barrel and a 16.5 " barrel....

http://bulletin.accurateshooter.com/...velocity-test/

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Black powder was known to take a long time to burn all the powder, this is why they had such long barrels for heavier loaded smoke poles back in the day, in the case of modern powder you can run into situations where shorter barrels actually have higher velocities if faster powders are used, but this theory for lengthening or shortening only goes so far and as you say 7% or so. The 308 test there showed a shorter bullet (110gr) having the largest velocity drop per inch but still no where near what is seen here.

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Originally Posted by Fox

It is not that I do not have an open mind, it is that I find it really hard to believe that 2in of barrel length will have a 30% drop in velocity.

Here is a link to a test that was done with a 308 Win.

http://bulletin.accurateshooter.com/...barrel-length/

What I am saying is that if your powder is matched to the bullet (using published data) then losing that much over 2in does not seem to click based on a lot of testing. If you are running a significantly shorter barrel like a 16in trapper 30-30, do not expect to get the same velocity of a 24in barrelled rifle but you should also not have a 30% loss in a couple inches.

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As per one of my previous post 50 fps/" is what I'm used to.....
Maybe the datas are wrong, powder charge or MV?!

I shot roughly 30 rounds or so of this load. It's the drop that point me to an issue of MV and the chrono proved it. I'll will shoot an extra 5 rounds just to make sure I didn't missed something.