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Discussion Starter · #1 ·
Thanks guys for all your help here. I had posted earlier this week that I have a new 17hm2 452 American that the barrel IS NOT floated.

Scope is a Leupold 3x9x33 EFR AO with adjustable Target Turret on elevation knob. Scope is mounted in Leupold 13mm Ringmounts (fit very well) Also has Rifle Basix Trigger and J&P Spring and action screws (they are really nice).

I stated that it "popped" in / out of the stock rather tight and had barrel stock contact the full length of the stock.

Everyone said shoot it before opening the barrel channel, especially since the Test Target was a 1/2" target.

Well I can attest to the fact that not all have to be floated to be SUPER shooters.

I am impressed!

Here is another pic of the test target and the target shot this morning at 100 yds and 50 yds. There are 5 shots each at 100 yds and then 1 shot each at 50 yds.



 

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Nice....................I'd say you definity made the right decision, I'll be doing the same testing with the new American, if it ain't broke don't fix it!

Gerald
 
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Well, they're designed to be, and leave the factory, free-floated. If you want to leave it as-is, that's up to you. The wood warped during the trip overseas, and is responsible for the barrel touching the stock. If it were my gun, I'd correct the problem. But it's not mine. With the wood touching the barrel like that, atmospheric changes are going to affect the pressure exerted on the barrel. Not to mention that any contact at all gives you the potential for a different point of impact for each and every shot. Try this experiment: take it out of the stock, put a washer or two on each action screw to temporarily free-float it. See how it shoots with no barrel contact. If it's not better, remove the washers and enjoy it with the barrel contact. I highly doubt it'll be better with that contact, however. That contact introduces randomness. Removing the contact introduces more repeatability. Remember, every time you shoot, the barrel moves. If it's touching something, that means it can move differently from shot to shot. If it's not touching anything, it'll do the exact same thing with every shot.
 

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To me the only non-floated barrel configuration that makes any sense is the single pressure point at the forward end of the stock. But even that is sensitive to the environment and your zero will wander. If the stock is touching the full length you WILL see zero wandering from range session to range session and it will not just be vertically but almost never in the same direction.

I have a Volquartsenized 10/22 in 22LR. It has their laminated stock which includes a full free floated stock with a small thin rubber pad at the very front of the stock. Maybe it just dampens the barrel vibrations or actually provides support (???). But the gun does shoot well (1/2 inch average of five 5 shot groups at 50 yds which is only an 1/8 inch behind my Anschutz entry level Silohoutte rifle!) and the zero wandering is minimal.

My CZ Varmint in 17HM2 was suppose to be free floated but the trip over the ocean warped the stock (as many others here have reported too) and it touched on one side. I free floated it before even shooting it to avoid the wandering zero problem. It shoots with the 10/22 for accuracy but only with Eley ammo. The others ammos makes groups twice as big. I have not seen any blowouts, by the way.

LDBennett
 

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Discussion Starter · #5 ·
Thanks for the responses, is there any danger of it shooting worse by floating the barrel.

How far back should it be opened up i.e to the step up or all the way to the action?

As good as the barrel fits the channel the entire length I have doubts that is was ever floated.
 

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Mark A:

I don't have an American but a Varmint so I have no personal experience about whether it was floated or not when it left the factory. But you are the first person here that I have read that said their CZ 452/3 barrel appeared to not have been floated at the factory. All have said the barrel on their CZ 452/3 (which model did they have ???) was touching only on one side and appeared to have been floated at the factory. I have several CZ centerfire rifles and all of them are floated from the factory.

The best approach for floating is all the way to the receiver. But some of this series guns have a barrel mounted front stock screw and if that is the case with yours any floating further back than that is probabley not necessary or that front stock mounting screw removed and the barrel fully floated.

I say do what is easiest first, then test the gun for performance accuracy wise. I would test it multiple times over the period of all four seasons to see if in the non-floated condition it has a wandering zero or accuracy degradation. If it is fine then do nothing. Spacing the stock off the barrel temporarily may give you insights as to the accuracy potential for a free floated barrel to help you determine if you want to do anything at all, but remember the biggest problem with non-free floated barrel is zero wandering with changnes in the environment over time.

The test for free folating is freely passing a dollar bill between the barrel and the stock from the front of the stock to the receiver.


LDBennett
 

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You roll the dice and take your chances...

To float or not? Its like playing craps- Pass Line or Don't Pass Line (Risk vs Reward)

It shoots good enough, then you leave it... You might get some POI shift with varying conditions... You may not...

If you float it (then seal the wood which you exposed to keep it stable...), it may do worse... May do better... If it does worse then you'd probably need to play with a pressure pad under the barrel to dampen vibrations... May also want to bed it while you are at it...

Mine is floated from the factory(but barely). I do find only a sheet of copy paper will slide under the barrel to the step, but it seems as though there is some friction (possibly a lite pressure pad) near the end of the forend...

I am looking to bed and float it then give it an oil finish this summer... need to get a few more items first... (parts for a poor man's trigger-job, hex head bolts, perhaps some pillars...):yippee:

Its not bad as is, but I think it'll do better... Its just now really starting to settle in after about 500 rnds down the tube... Its just a hunting rifle, but I want it to look as good as it shoots... with a trigger job and bedding, I think I will be well pleased...

If it doesn't do better than I'll start playing with pressure pads from rubber (I use the lil square patches for bicycle inner tube repair kits...)

I am willing to risk it as I have only had one rifle shoot worse after being floated... Then a full bedding job made it really shine... WHat you do is your choice... But me, I like to tinker...:bthumb:
 

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Don't fix it if it is shooting good. I have an American in 17HMR and it was shooting good then I opened up the channel and the groups opened up. Took me some time playing with a pressure pad in the channel to find the right placement and torque on the action screws to regain the groups again.

APEXDUCK
 
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I suspect you mean groups opened up with the ammo you had on-hand at that time that shot well in its previous state. Changing something like this will almost certainly mean starting from scratch as far as ammo goes, finding what it likes all over again. It's not a very good assumption to think it'll behave the same way with the same ammo when you're changing how the barrel behaves.
 

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Discussion Starter · #11 ·
I suspect you mean groups opened up with the ammo you had on-hand at that time that shot well in its previous state. Changing something like this will almost certainly mean starting from scratch as far as ammo goes, finding what it likes all over again. It's not a very good assumption to think it'll behave the same way with the same ammo when you're changing how the barrel behaves.
That kinda sheds new light if I have and only intend to shoot ONE ammo thru this gun....................ELEY!

It HAS to like eley or reside elsewhere.
 

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Every rifle's barrel vibrates with the firing of a cartridge. The trick is to get it to vibrate exactly the same with every shot. If the stock touches the barrel it stiill vibrates but at a different rate. Move the way you support the stock on the bench or with your hand on a rifle that is not free floated, and you may change the way the barrel vibrates. Free floating isolates the barrel so you minimise the impact of the way the gun is supported. Of course environmental changes on a non-free floated gun can warp the stock and move the zero or even just shooting it can move the zero.

Barrels vibrate at many rates at once but the basic rate (the lowest frequency) has the biggest impact on the rifle accuracy. The action of the barrel is sinusoidal (both positive and negative in a wave like pattern). If the bullet leaves the barrel as the barrel is in the mid point of the total excursion (zero), the rate of change is the greatest and the effect on the bullet is the least predictable shot to shot. If the bullet leaves the barrel at either the peak or trough extremes the barrel is instantaneously stopped and approached that point at the slowest rate of change. That's where you want the barrel to be when the bullet leaves. But change anything like where the stock touches it and the frequency changes and the accuracy may go away shot to shot. Free float the barrel and, regardless of the support of the gun or the weather, the bullet always leaves at the same point in the motion of the barrel.

If the point where the barrel meets the receiver (which touches the stock) is not sturdy enough that may effect the barrel vibrations. If the stock to receiver mounting is not the same with every range session or from shot to shot that can effect the barrel vibrations. That's why torquing the receiver to the stock is important and/or why pilar bedding appears to work better as it offers a stop that assures the receiver to stock fit is always the same. That's why Volquartsen offers a 10/22 receiver/barrel combination that screws together rather than the v-block standard configuration.

You must find an ammo that will cause the barrel to vibrate in such a manner so that the bullet leaves the barrel at the extremes of the barrel sinusoidal motion. Finding tht ammo is trial and error but possible especially with all the possible choices of 22 LR ammo. If you change anything that affects the dampening of the barrel (pressure points or free floating or ??) then you impact accuracy. You must again find an ammo that puts the barrel at the extremes of the barrel sinusoidal motion for the new characteristics of the barrel.

Eley makes all sorts of ammo. They price it by consistence of its manufacturing quality. Their best ammo may shoot well and may not. Their cheapest ammo may be less consistent but consistent enough to hit that magic frequency that we need for max accuracy. Other manufacturer's ammo may also hit the magic frequency too but have is accuracy impacted by it inconsistent performance. Its all trial and error testing. Sometimes you can add a pressure point and change the vibrations to the barrel such that an ammo that was not previously accurate becomes accurate. But its a crap shoot. Free floating the barrel removes most of the varibles but still requires that you fine the ammo that the makes the barrel vibrate so that the bullet leaves the barrel at the extremes of the barrel sinusoidal motion.

Sorry to be so wordy but that's what it takes to explain scientifically what is happening.

LDBennett
 

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Discussion Starter · #13 ·
Eley makes all sorts of ammo. They price it by consistence of its manufacturing quality. Their best ammo may shoot well and may not. Their cheapest ammo may be less consistent but consistent enough to hit that magic frequency that we need for max accuracy. Other manufacturer's ammo may also hit the magic frequency too but have is accuracy impacted by it inconsistent performance. Its all trial and error testing. Sometimes you can add a pressure point and change the vibrations to the barrel such that an ammo that was not previously accurate becomes accurate. But its a crap shoot. Free floating the barrel removes most of the varibles but still requires that you fine the ammo that the makes the barrel vibrate so that the bullet leaves the barrel at the extremes of the barrel sinusoidal motion.

Sorry to be so wordy but that's what it takes to explain scientifically what is happening.

LDBennett
Yes sir, I understand and appreciate the harmonics involved quite well, BUT this is a 17hm2 so it is limited to a handful of ammo choices.

This is what makes me hesitant to think I can "find the right ammo".

Thanks very much for all help!
 

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Mark A:

My CZ varmint likes Eley. Your 17HM2 might like one of the three other choices: Hornady, CCI, or Remington. Yes, some here say CCI and Hornady are made in the same factory and that Eley makes Remington but it sure doesn't hurt to test. In my gun CCI and Hornady grouped the same but Remington and Eley most certainly didn't. Others have found CCI to be superior in their gun and still others Hornady. You have to test to be sure. Out of the four one will be better!

Sorry about the dissertation but others may not understand it all. It can't hurt to educate them, can it?

LDBennett
 

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Mark A,

Just to add to the excellent explanation by LDBennett, different production lots of the same ammo will perform differently. My Marlin HM2 loved the first Hornady I bought with the rifle (only 200 rds :( ), the next Hornady I bought ( different lot #) nowhere near as good. In my experience, the Eley has been the most consistant from lot# to lot#. Overall, very little variation in performance or group sizes compared to the U.S. manufactured ammo.

So far, my American in HM2 likes the Eley the best.

Jay
 
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