Just see Gerard's post for the truth of the Somochem point.

Jeff, your behavior is surprisingly aggressive, rude and boorish for a moderator. But perhaps that is how Saeed wants you to act.

quote:

Originally posted by starmetal:

quote:

Originally posted by Pegleg:
I always shoot my rifles with a coat of oil in the bore. Just not a thick coat.
First shot is for lube and then the graphite in the powder takes over.

Okay, why not a thick coat...hmmmmmmmm?

Cause it would stain my boots when it ran out of the barrel!

Dan,
Let's not turn this to personal insults, shall we. there is no reason to resort to this type of behavior when one has merely made a mistake or has a misunderstanding of the facts associated with it.

Gerard's post clearly states that perhaps somchem didn't make the statement, rather johan did.



If you find a quest for knowledge to be rude or boorish, sorry, it's not likely to change

Your statement was that Somchem lab's made a satement of position. They have denied this.

This is irrefutable.

That an employee of somchem may have made those personal statements certainly could have happened. Yep, sure enough, but not as a lab position statement, or anything they have record of.


So, in effort to actually have EXPERT opinions on the matter, I have asked Somchem and ramshot (amoung others in the field) for their either position or opinion as to the effects of twist and pressure on internal ballistics.

quote:

Originally posted by 500grains:
Jeff, your behavior is surprisingly aggressive, rude and boorish for a moderator. But perhaps that is how Saeed wants you to act.

Dan,
As one can clearly see, I am interating as a poster on the forums, interacting with another poster, and not picking a fight in any means.

This should be a simple factual discussion, without name calling.

One could say that "your behavior is surprisingly aggressive, rude and boorish for a lawyer and gun writer" but you aren't acting in that role either.

So I won't, and let's don't

quote:
Greetings,

I heard that your company performed a test on varying twist rates and that effect on pressure.

If so, could you please forward me a copy of this document, as I am greatly interested in the general effects of increased twist and pressure in small arms barrels.

if not, please let me know

jeff smith



Answer
from Manie Johannes, Somchem/DLS-WC, Ballistic Proof Range

quote:
Jeffe

Sorry we did not do any test on the verification of the twist and the pressure accompanies it.

So we don’t have any documents regarding these test.

Manie Johannes

DLS-WC
Ballistic Proof range

There is some doubt in my mind as to the authenticity of this above post. One could make a good argument that it was fabricated. Your original email was signed Jeff Smith but the response back to you was Jeffe, your forum name but that was mentioned no where in your email. Maybe you should delete my message and go clean up your posts so no one will see them.

quote:

Originally posted by Customstox:
There is some doubt in my mind as to the authenticity of this above post. One could make a good argument that it was fabricated.

you have the original email in your mail box

quote:

Originally posted by Customstox:
Your original email was signed Jeff Smith but the response back to you was Jeffe, your forum name but that was mentioned no where in your email. Maybe you should delete my message and go clean up your posts so no one will see them.

Chic,
you have mail, I sent you the enter email reply and thread. Email them yourself and verify.

as for "jeffe" my email id reads, when an email is sent to someone
Jeffe <jeffeosso AT weaponsmith.com>

Let us know how that works out for you, have a nice day.

Actually...
i built 2 and bought a 3rd, 358 winchester to test this very idea.

1x16 (savage 99) 1x12 and 1x10 douglas barrels.

across the board the 1x10 produced higher repressures, without a doubt.

in fact, TWIST is specified in both SAAMI and CIP for rounds, as it is KNOWN to change pressure.

for example, you can not buy a 470 NE with faster than 1x18 twist, and that is ONLY if it's an american rifle... nominal is 20 and 22, saami and cip (but I forget which is which)

BTDTGTTS

If you took a 223 and built total max safe loads in a 1x12 and stuck them in a 1x7 you will, without a doubt, have a pressure excursion above saami.


jeffe

BS! If you did see differences in pressure in the three rifles above, it had little if anything to do with the twist. Three barrels from three different manufacturers with three different throat, chamber, and rifling specs. All these factors have a MUCH greater effect on pressure than a slight increase in twist, particularly in the range you are talking about. And please do not tell me that all had saami spec barrels. The manufacturers do whatever they want with throat and barrels dimensions, and they certainly do not throw away a reamer when it gets a little wear. We build match AR-15's, lots of them. I have used twists from 1-14, to 1-6. I have yet to find that twists in this range have any effect on pressure. I shot a whole season with a 1-6. using the same very hot loads that I used in my previous 1-8 and 1-6.5 barrels. Guess what, I could not tell any difference in pressure, and it shot just fine, good enough to get me on stage at Perry and win a few state championships. These same loads have blown primers in a different 1-8 barrel. This no more proves that a 1-8 generates more pressure than a 1-6 does than your little test proves that a 1-10 produces more pressure. There are so many other factors that have a MUCH larger impact on pressure.

I got a call yesterday from a guy who wanted a 1-8 krieger rather than a 1-7.7 because he has heard that the 1-7.7 would not last as long because the higher pressure caused more throat erosion. I guess he has been reading threads like this one.

John

John,
on the 1:16, you could be right, as it was a used gun when I got it... the douglad 1:12 and 1:10, well, they were cut with the same reamer and barrel drill, but different buttons.

So, two makers, sure enough.

That a load blew primers in another barrel is an entirely different story, but one to be noted as something to look out for FOR SURE.

jeffe

jeffe

Jeffe,

quote:

quote:
Originally posted by Gerard:
The person at Somchem who originally mentioned the non event of pressure / twist rate relationship to me was Johan Loubser.

I do not know if Johan did formal testing along twist / pressure lines or whether he investigated the premise and found so little merit that it was not formally pursued. I will try to find out.

Gerard, without I doubt I recall your passing statement on this. However, then, as in know, SOMCHEM never made the statement that the twist could be disregarded, as Dan states

You highlighted the wrong part of my post. Johan Loubser headed up the Somchem Proof Lab for more than 15 years. Johan Loubser WAS the Somchem Proof Lab and Manie Johannes and his team still consult with him regularly. He was not just another employee or some nondescript grey suit who happened to be working in the building. You could not have known this so your comments are understandable.

I originally posted the statement that Somchem found no merit in tighter twist / pressure as a line of research (because it is a non event). I have no reason to doubt it as it came from the head of the department at the time and, if you want to take someone to task about it, it should be me, not Dan.

Let us know what reply you get.

Dan,
You will get no reply if you address him as "Chris". He has another name now.

Gerard,
Research labs document everything they try, as to avoid it again, if false.

I really wasn't trying to start a storm, I was trying to see the data that said this. Since it's referenced as somchem, I figured having their data would start it out right.

I guess it was johan's personal position, not SOMCHEMS position.

which makes it an entirely different statement...

"A ballasiticians says" is different than "the offical position of SOMCHEM is"

jeffe

quote:

Originally posted by Customstox:

There is some doubt in my mind as to the authenticity of this above post. One could make a good argument that it was fabricated. Your original email was signed Jeff Smith but the response back to you was Jeffe, your forum name but that was mentioned no where in your email. Maybe you should delete my message and go clean up your posts so no one will see them.

Dan,

My email is styled as

quote:

Date: Wed, 21 Feb 2007 16:54:53 -0800 (PST)
From: Jeffe <jeffeosso at weaponsmith.com>
Subject: twist rates

Wow, it's a conspriracy.... JEFFE is my commonly used name....

shoot me your email at jeffeosso at weaponsmith.com and i'll forward you somchem's reply

Pretty simple stuff, and I am always happy to share my data with those discussing the other side.

Why was Uncle Enfield's post deleted???

Now Jeff's post disappeared too.

Jeeez. Next think I know, Somochem's technicians will start disappearing as well... And I thought Stazi was bad.

quote:

Originally posted by jeffeosso:

quote:

Originally posted by 500grains:
Hi Chris,

Do you agree that twist rate is basically a non-issue with regard to pressure?

Dan,
No one really believes this, sorry

Dan,
Good! Did you figure that one out on your own? I have been wanting to ask Warrior if he is Chris Bekker, as a little birdy told me.

Seems very possible Warrior has been pegged as an alias of the banned Chris Bekker. Thanks.


Jeffe,
You are fabricating emails from Somchem???

Back on the 17 page Chubby Checker thread (Do the Twist!) this has all been circle jerked to death. At least that thread provided the vehicle for the introduction of the .395 caliber rifle bullet to the world by Father Gerard and I.

Artillery tests of 1:7.5" twist compared to 1:15" twist showed pressure changes on the order of less than 1%.

If you do the math with the angular/rotational kinetic energy versus the linear/translational kinetic energy, as engineer Don G did for us, that would also point to about 0.5 PER CENT magnitude of pressure changes between the 10" versus 15" twist rates.

Thank you for this opportunity to plug the .395, which shall use a 1:12" twist with 340 grain monometals. There will be no cause for meaningless whining there.

Hi Ron, I did not know that Chris's new handle was a secret.

Thanks for the info about artillery pressure testing. As Art A. pointed out, artillery pieces work according to the exact same principles as a sporting rifle.

CB thought it was a secret.

I didn't realize that this would start such a debate. The answer seems to be don't worry about it, pick the twist that will handle the heaviest bullet you intend to use & work up your loads.
It looks like this will be one of those situations where you won't know for sure until you do it yourself.

hvy barrel,
Tell us the caliber, what you intend shooting with it (small to large) and the ranges you are likely to shoot at (probable closest shot and probable longest shot). For what it is worth, I will tell you what twist rate I would use. Use it, dont use it, it is only an opinion but you would have the benefit of the mistakes I have made.

I guess I am like every other shooter/hunter on here, I want them all. To answer your questions though, I am currently thinking about 3 different cartridges. The 22-250 improved, the 260 Rem. & the 6.5-06.
The 22-250Improved I was thinking about using a 12" twist with 55gr bullets. I have a standard 22-250 with a 14" twist that shoots 55 grainers just fine. This got me to wondering what the difference would be between two rifles that were identical except for the twist. I know in my example there would be no detectable difference without expensive & sophisticated testing equipment. What about an extereme difference though, like going from a 14" to a 7" with the same light bullets. Then I got to wondering if other things would happen. Would the bullet be apt to foul the barrel because of its resistance to start turning at first, or would the bullet be slower out of the 7" than the 14".
I thought that the best place to ask such questions would be here, there is alot of knowledge on this forum.
Gerard to answer you question, I am considering a 22-250improved to shoot 55gr bullets for shooting paper, prarie dogs, groundhogs, rock chucks, & coyotes. Basically any varmint I can. The distances for paper would be no more than 300 yards, that is the longest range I have access to, on the varmints, as far as I can shoot.
The 6.5 calibers I mentioned earlier will be intended for the same targets with the addition of antelope & whitetail. The distances I have in mind for whitetail are between 15 & 100 yards, for antelope it could be out to 500. I am not sure about the bullet weight I would want to use for these two applications. I am considering a barrel with an 8" twist for the 6.5mm.
I hope that I didn't ramble too bad & that I answered your question.

quote:

Originally posted by eddieharren:
When striving for absolute accuracy, the slowest twist rate, that will stabilize your bullets, is recommended. Faster twist rates will shoot well with the lighter bullets. They just won't shoot as well as the slower twists.

Correct! You CAN "overstabilize" a bullet, at least as far as the optimum twist for a given bullet length is concerned. But it is not the problem it used to be, now that we have much better bullets...