Can you guys tell me (clean up language) this guys is trying to say?!?

[joshua99ta]

i found this on a forum not pertaining to guns at all but there is a sections for guns and hunting and stuff .... so can SOMEBODY translate the point this guy is trying to make?!?


How many of us here shoot something like a 50 or 55 grain bullet in a 1:8 or 1:9 twist .223? Or maybe a 1:8 twist in one of the various 6mm rounds? We all have at onetime or another.
Last night I was up late with Parker and his wisdom, and here's some thoughts I stole out of his mind:

* the bullet enters the rifeling, and starts a chain reaction as well as the well known reaction. When the bullets enters the rifeling it actually twists the barrel as it is pushed the the barrel, and the the like reaction occurs when the barrel will actually uncoil. In otherwords the barrel becomes a giant coiled spring

* The difference in energy lost from the rifeling in a 1:14 twist barrel and the now in vogue one and eight twist is roughly 25%. It takes much more power to push a bullet thru a fast twist barrel than a slow twist barrel. When you increase the resistance to the bullet going thru the rifeling you also induce a like action into the barrel material, and as the bullet passes by the like reaction occurrs with the barrel trying to "unwind" (I bet Calffee never thought about that one!!). So in the end the more resistance, the more stress is added into the barrel after ignition

* Now that we've completely abused the barrel, lets see what elses happens. The bolt is the next victim. As the barrel tries to twist, it also tries to move the chamber end, and the bolt face (the hotter the load the more pronounced this is). This energy is then transfered to the actual reciever frame. Then of course it over reacts the other way on the return trip to the static position. We ain't done!

* how many of us have just had to have a "speed lock" kit? GUILTY as charged! Light weight firings pins and heavy springs are nothing but a crutch to help fix an engineering problem. (Mauser, Winchester, and 700 Remingtons come to light here). Think about it a minute; the case slides into the chamber very easilly, so it obvious there some clearence there (as it should be). You lock the bolt into position to then set the correct headspace (I hope you did this right). You release the firing pin and it strikes the primer. The rest is history. But alas we all want those magic lock time numbers. We add a titanium firing pin (a harmonic distortion problem in itself), and a spring that looks and feels like it's a left over purple stripe race hemi valve spring. Now the firing pin hits the primer like a sledge hammer, and actually shoves the case forward (so much for headspace). It hits the primer so damned hard that it acts like a tap dancer in the face of the primer. If the firing pin strikes a few thousands off center it cocks the case sideways ever so slightly creating a displacement laterally. What we should be after is one clean strike just good enough to set the primer off on a dead center axis to the centerline of the case. But alas we had an engineer design into this equation a four inch long firing pin and a very short bearing surface to guide the firing pin into the primer. In reality a 1.5" firing pin is all we need in a properly designed bolt. Use a small return spring (both in weight and size). Without the spring being contained inside the firing pin itself; we also take all the harmonics associated with hardened steel out of the firing pin. And the return spring acts as a shock absorber. Anybody here know what the lock time king is? I'll give you a hint; it's none of above and they also are not pretty.
gary

[BobbyL]

Some good points and some bad ones but either way im not about to touch this one.....

[joshua99ta]

LOL I just thought it was funny that he made these statements and gave no reasoning as to where the origin came from or a point of making these statements...

[Coyboy]

Ask Trickymissfit, almost sounds like one in the same.

Basically talking about the tourque produced by fast twist and Heavy bullets. Really not going to feel it in a .224 bore shooting 55 grain bullets. Now a 308 or338 shooting heavy bullets it is very noticable. Been a known and adressed issue for quite some time and has been adressed by action and stockmakers alike.

The lightened fire pin and heavy spring has also been a known issue for about as long as it's existed. In BR rifles a well known HOF has proven his rifles shot better with the standard bolt guts.

Not alot of enlightenment in this guys post.

[winmag]

Probably a college kid, who jumped off the deep end at a party, and got all warped in the puff puff give sequence....... Too bad. If he had a decent knowledge of firearms there was hope at one time, but after a post like that Im affraid he's joined the dark side. Saw some crap like that happen to a couple guys I knew in college. 1 day they were normal country boys, the next they turnned into hippie stoners. What a waste!

[J E Custom]

Originally Posted by BobbyL

Some good points and some bad ones but either way im not about to touch this one.....

Good advice !!!

But this is a discussion web site .so I will attempt to shed a little light on some of these
statements if I can.

First= as cowboy said it is not a problem with light bullets unless you have an extremely
light barrel contour like a #1 and even then it probably wont have enough effect to worry
about. most people use heaver barrels and this all but eliminated this phenomena.

This does occur in large bore rifles with heavy bullets and light barrels but not as bad as
the poster made it out to be. It does not straighten the barrel rifling out. In fact the high
speed film of a tank barrel upon firing only showed about 3 to 4 degrees of rotation with
a very large projectile.

So with proper bedding and barrel diameter this effect can be controled to a point of no real
effect on accuracy. one of the main reasons that bench rest shooters use heavy barrels is
stiffness and torque resistance.

Fast twist barrels are to stabilize the heaver bullets at the slower velocities they reach. But
can be problematic if lighter/faster bullet are used because of jacket separation from the
Inertiaof the bullet when coming in contact with the rifling. This a good place for gain twist rifling.

The slower the twist with the same velocity the less chance of this happening but the greater
chance of not stabilizing the bullet, so the proper twist rate is very important.

As to the issue of velocity difference between a 1 in 14 and a 1 in 8 twist = it is no where near
25% more like 25 to 50 ft/sec at best.

Now for the fireing pin issue.
The main reason for going to a lighter fireing pin is to improve lock time !!!! the reason to
improve lock time is to make up for inconsistent trigger control by the shooter (The faster
the ignition process the less time the untrained shooter has to move positions or follow
through). this is one of the reasons that the well trained and practiced shooters find no
advantage in them.

The heaver spring improves the lock time but it also makes up for the loss of inertia of the
lighter fireing pin.

Also any fireing pin will move the case forward if the head space is improper but it can't "Drive"
the case beyond the allowable headspace. And if the firing pin protrusion is correct the firing
pin stop prevents very much of this from happening.

Another reason that I use the speed lock springs Is the diameter . they are smaller and will
normally reduce the drag of a serpent like spring inside of the bolt (The smaller diameter
spring coils in line and does not touch the inside of the bolt.

All of the things he mentioned can cause some problems if combined in the wrong
combination but most gunsmiths that build accurate rifles know how to avoid these problems
areas and don't worry about the theory just work around it.

This is just my opinion based upon my experiences and is certainly not the last word in these
areas.

J E CUSTOM

[joshua99ta]

Thank you JE!!!

I kind of read the post on another forum and I was thinking "this guys is smoking some good stuff" I've done lots of reading and these points he brought up have never been something I have read about. I'm no accomplished long range shooter by any means.... I'm still a beginner and have been without a rifle to actually do any shooting for almost a year now.