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  #11  
Old 01-19-2015, 06:23 PM
260Ackley 260Ackley is offline
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Can you still see your hits through the scope with that light of a barrel?
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  #12  
Old 01-21-2015, 09:24 PM
17tbs 17tbs is offline
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Yes, hits are easily visible, 3 to 4 lbs recoil energy is totally negated by the 5 pounds of the rifle, very little jump or movement is apparent, even with full power 30gr loads in the heavy 18.75" barrel, scope movement is very minimal, in the composite barrel, the total weight is just over 5 lbs, so, with the light loads for that barrel using about 1.8 to 2.2 grains of IMR700X, and generating between 1800 to 2350fps, the rifle barely even jumps. It is surprisingly loud, partly due to the short 16.5" barrel, and the powder choice. (Edit: I do not have any actual chronograph data using this powder combination, I have interpolated what it should do based on others reduced loads using lite loads of Unique in the .223 for reduced loads with 35gr HNDY, thru 55gr fmj and my own chronograph work using IMR700x in the .223 with bullets from 40gr hornet, 40gr .22 Jet, 45gr Bee, 55gr Rem FMJ, and 70gr Speer. )

Last edited by 17tbs; 05-18-2017 at 08:34 PM.
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  #13  
Old 01-23-2015, 07:40 PM
Raid5 Raid5 is offline
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Default Nice project.

How hard is it to remove the barrel? Do you have a picture of the complete rifle? How about making a switch barrel by using a set screw to hold the barrel in.
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  #14  
Old 01-23-2015, 09:41 PM
17tbs 17tbs is offline
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Default vha switch barrel.

The barrel locks in with a Savage type barrel nut, a dovetail lock just aft of that, a set screw below the scope base integral to the base, and the case extractor.

Removal is with either a spanner type wrench on the nut, or with a pinned hex collar that slips over the barrel nut.

Removal and installation takes about 3 minutes, and two tools.

It also holds and returns to zero after re installation, the lock up is over a 4 inch span with a very tight fit on either end of the stub to the swapped barrels.

Last edited by 17tbs; 01-24-2015 at 03:34 AM.
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  #15  
Old 03-01-2016, 08:39 AM
17tbs 17tbs is offline
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Smile Update on light 17vha loads

1.8gr IMR Hi Skor 700X, Fiocchi unfireformed case, 25gr Hornady HP Moly coated, consistently grouped under 1/2".

Bullets were seated just into the lands
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  #16  
Old 03-18-2016, 07:14 PM
17tbs 17tbs is offline
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Smile First hunt

Well, 29 loads, finally in the field & I fired all of these through the composite barrel. Loads were 1.8gr of IMR Hi-Skor 700X, I will refer to simply as 700X, to 2.6gr of 700X. Most of the shots were at close range due to high wind. The majority, 16 loads were using 25gr HNDY HP Moly. Since I did not bring a chronagraph, I referred to JBM.COM to reverse solve for the exterior ballistics and velocities based on observed POI at 25 and 50 yards where the bullets were landing on the crosshair. It appears if things are correct, (and they might not be because this isn't enough data), then the velocity was somewhere around 1400 fps. Going to do the calcs to confirm, 25gr HNDY FBHP and 50 yards POI, 4500 ft altitude 70°F, low humidity. The data then match the calculation, and that is about as good as I can do without a chronograph.

So a pretty poky load load if the numbers match. Why try this excercise?

Lets back up here a bit and recall what the composite barrel was intended for, mainly it was to test barrel harmonics using what at the time I thought would be a super whippy barrel.



Half of the barrel is essentially an unsupported Redman liner in an aluminum and boron-graphite composite shell supporting the liner at various points where I had considered it to likely be effective at dampening some of the frequencies of vibration. The rear half is a steel sleeved breech section from what started as a section of .280 Remington barrel acting for the first 4 ish inches as the engagement/alignmnet region in a threaded stubb from an old TC 22lr barrel that had seen better days. The next 4 inches of the .280 Remington is tapered from 0.680" 0.440" to engage the composite sleeve.



What happened ? Well, I don't have what I wanted, which was a platform for testing barrel whip/vibrations. The short 16.125" barrel was having nothing of it. It does not fling bullets exiting at various velocities in wildly different directions. No, it is a failure as such a tool because it piled most of them into a tiny ragged hole at 25, 50 and 80ish yards. One click on the scope moved poi stubbornly 1/2 a bullet diameter at 25 yards. It did this with ALL the loads, not only this, they grouped together at all velocity loadings with both the 25gr HNDY HP Moly, and the old Remington 25gr PLHP. Perhaps this is because the velocity is low enough that high degrees of vibration are not being genetated, or more likely that the composite structure of the barrel has severly dampened those vibrations, and they are no longer harmonic.

SO, ... failure? Yes, no, it isn't the test bed I intended. But not bad for what it is, a really light centerfire rifle, and with either barrel it shoots into a raged hole under 80 yards, and sub half inch groups are pretty easy at 100yrd. Will the composite barrel do this well at over 100 yards? I don't know, but if I had a more powerful scope on it I could test that idea. As it is, with a 2-7x VX2 Leupold it shines as a close range precision lite carry rifle. Am I happy? Well I had a grin on my face a Cheshire cat would envy.

Bullet performance was the next question on my mind, so with the maximum 2.6gr 700X 25gr HNDY HP Moly load I went out on foot through the brush to see what it would do on a bunny. (Edit: I will have to switch powders if a chronograph confirms the velocity of around 1400fps with 700X).

That load is fine if you want to leave about an inch and a half hole through a medium sized bunny. It is not pelt friendly, entry was what I could only call roughly chopped shoulder, exit was a mushier consistency. The bunny did not explode, it did die very quickly. There wasn't evidence of lung involvement, but it was right in there where if a vmax had been used you would have expected bloody nostrils, or a bunny cut in two. Very little fur sprayed on the tangle of brush where the bunny had considered itself safe, nor was there any spray of blood or tissue. The range was about thirty yards. I was surprised by the performance on the bunny, because on a large soft ripe apricot it did not display such expansion, though it did create a stellite entry and exit. If 1400 to 1300fps is actually that effective with the 25gr HNDY FBHP then I wonder why more people do not consider it for a game/meat bullet and velocity combination. It mimics to a large degree what the ubiquitous .22"lr does. This can give the centerfire .172" a dual use, so you only need to carry one rifle, not two. Any .22"lr that groups in the sub 1/2 MOA range is a keeper, so, by that "standard" this one is as well.


I must give credit and thank a Saubier.com forum member for doing the majority of the metal work creating the TC barrel stub and creating as far as I am aware the only TC stub with a hotswap field set of barrels using a Savage style nut system. I do not know if he would consider repeating the effort because it was a bit of challenge, though it is possible. The hardest part may have been the fitting of two barrels to the same stub, or it could have been reaming a very precise 0.31015" hole down a section of .280 Remninton barrel, (used as the breech of the composite barrel), to the chamber area then stopping at the precise location to allow me to ream a clean shoulder in the chamber. He heard about the idea here in this post, and took the idea and ran with it.

Many of the forum members have him to thank for success in building their own TC barrels. I can't thank him enough.

In closing, the rifle and cartridge perform as hoped with one failure in designed and intended performance, the whippy Redman liner composite barrel failed to create a visible pattern from barrel vibration and differing velocities with different bullets. The 17gr Vmax does print a tad higher, but still in a tiny cluster when using different loads of 700X from 1.8gr to 2.3gr. I could load a 20gr Gamepoint faster but it would not be what I want, a centerfire .172" useful for replicating the rimfires from the 17 PMC Aguila with its 20 gr game load, to the 17 HMR. Using all of the velocities and bullets available to .172 caliber fans I can get most of what I need from this tiny cartridge and rifle. A 30gr Berger, Nagle, or the 30gr BTHP Kindler won't likely be stable at the lower velocities achieved from the composite barrel, but the 30gr bullets do shine in the longer 18.75" non composite barrel.

Last edited by 17tbs; 03-20-2016 at 03:30 PM.
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  #17  
Old 05-18-2016, 01:59 AM
17tbs 17tbs is offline
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Default Update

Whippy barrel action can occur with hotter loads. Loads that are kept under 2200fps are not causing a whipy barrel action. The Redman liner in the composite barrel was torture tested this week using a series of 12 H4198 loads grouped in threes under some 20grain Gamepoint projectiles. These hotter loads produced moderate to full pressures within the first few inches but should have been below 14kpsi by the 5th or 6th inch down the bore so still technically well within the pressure limits of 4140 steel with the actual wall thickness at these velocities. Plenty of apparent barrel whip was evidenced by groups opening up to over a half inch at 50 yards using the same load, and subsequent loads up and down the velocity curve printed groups in locations up to 2 inches away from other sets of loads.

The zero was reconfirmed with some lower velocity loads in the sub 2000fps range using hornady 25gr hp and HS700X and it went back to chewing a nice little ragged hole. Barrel whip is apparently a thing that requires a pressure and velocity curve remain active through to the portion of the barrel liner which is unsupported by steel after mid course down the bore.

I haven't figured out whether to go further with this test and attempt to dampen the whip through some means, but it did confirm that barrel whip really was an impact on placement of groups even from changes in velocity resulting from changes in powder weights as small as 0.1 grain. The groups are still there in about a half inch separated from the other velocity loads by a wide margin, and it is mostly a vertical dispersion shaped overall like a football standing upright.

So, the lesson is learned, which is fairly obvious to all who shoot heavy barrel match rifles. Thin barrels are a definite detriment to overall accuracy when using different groups of ammunition. Groups may still be reasonably attained but consistent actual bullet time in bore and exit is absolutely critical to any hopes of a reliable zero. Warmer ammunition, colder barrel, etc become clearly noticeable factors.

860 fps into dry fracking sand, .86gr HS700X from the 18.75" barrel

Last edited by 17tbs; 05-18-2017 at 08:42 PM. Reason: Update
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  #18  
Old 05-18-2016, 02:21 AM
rickiesrevenge rickiesrevenge is offline
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Interesting. I've played with a few really light contour barrels. Maybe not as light as your project, but they were in bigger calibers too. The one thing they all had in common was that they were all finicky. Once the load combo was found they would shoot really well but I had to try a lot of bullets and powder combo's before that happened.

Aaron
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  #19  
Old 05-24-2016, 03:58 PM
17tbs 17tbs is offline
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Default Finicky

Yes, they are finicky at full rifle velocity 2000fps and up. At the lower velocity the whipping actually does occur but it must be really reduced. 700x loads in this if kept around 1.8 to 2.7gr actually print into just about the same POI. Consistent seating depth is pretty important as it affects bore time pretty drastically.

Incidentally, if you have a TC with a broken hammer spring, you can call Smith and Wesson, and get one shipped to you for FREE, YES FREE, NADA, ZIPPO!, meanwhile you can just actually use two large flat vegetable rubber bands for a field expedient fix if you are nowhere near a postal delivery box. Simply use your hammer and loop the bands lengthwise around your top scope cap, yes, I know that is about as ghetto as you have probably ever even heard of, but it works just fine in a pinch. (DO NOT EVER SHOW UP TO THE RANGE with this setup, you would be the laughing stock for a good long while.)

There is of course Mike Bellm who can supply you with five of them for about $20 should you ever want to have some spares to make friends with by mailing someone a freebie.

This is one of the many many reasons I love a TC, it is such a simple design that any monkey can fix it in a pinch. When it was designed someone was really thinking on all 8 cylinders. The Encore is actually significantly more robust, and should last a lifetime, but this is the only time since I purchased the carbine back in 87 that a component has worn out.

A good tip too think about is HOW to GET THAT CONFOUNDED HAMMER SPRING BACK INTO PLACE once you have your replacement.. ? well??/ I tried all manner of metallic tools to no avail, then I looked at the toothbrush sitting in m cleaning supplies stack, PRESTO, that worked, first try.

Last edited by 17tbs; 05-25-2016 at 07:45 PM.
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  #20  
Old 04-01-2017, 02:18 AM
17tbs 17tbs is offline
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Default 17gr XTP alternative loads

20gr xtp 2.68gr IMR700X CCI400 SR primer 2340fps,
20gr xtp 9.04gr 300MP CCI400 SR primer 3250fps,
20gr xtp 9.16gr 300MP CCI400 SR primer 3440fps
20gr xtp 9.26gr 300MP CCI400 SR primer 3558fps

20gr xtp 9.68gr 300MP CCI400 SR is unsafe

Best useful load probably is 9.16gr 300MP

Last edited by 17tbs; 05-18-2017 at 08:49 PM.
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17vha, barrel profile, tc barrel, walkabout carry rifle

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