Tuners

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BigAl
Posts: 312
Joined: Mon Nov 26, 2007 5:37 am
Location: Norfolk England

Re: Tuners

Post by BigAl »

As far as self compensation goes that has long be recognised in the fullbore world. The Lee Enfield .303 designs are well known for it. Well as long as you are looking at an SMLE or No 4. These rifles were well known to compensate given the rather variable nature of military specification ammunition. However this compensation effect is only really noticeable at long range, 800 yards and over. At those ranges they have much less vertical stringing then the ammunition suggests that they should have.

For the US members it is important to remember that the majority of rifles commonly seen in the US that are attributed to Enfield or even Lee Enfield are not of the same design. In fact they are usually P14's (built for British forces in 1914-15) if in .303 or P17's (built for the US army expansion in 1917-18) if in .30-06. Although these rifles were built in the US to an Enfield design they are actually almost a direct copy of the Mauser G98 action.

Until 1968 all fullbore rifles used for target shooting in the UK were actually ex service issue rifles, either SMLE, No 4 or the P14. It was not uncommon to find that a keen shooter would have two rifles. A P14 for shooting at short range up to 600 yards, where the stiffer, front locking, Mauser type action was an advantage to accuracy. The they would then have a No4 for long range, 800 to 1000 yards, as the compensation would help reduce the vertical stringing with the service issue .303 ammunition that was compulsory in competition. Even after 68 with the change to 7.62×51 when TR was introduced to replace SR(b) many shooters simply converted existing rifles to the new caliber. Even after caliber conversion the N0 4 action rifles still seemed to self compensate to a degree. At this point there were also a number of K98's converted to meet the new rules. It was not until 1982 that the top prize in British Commonwealth TR shooting, the Queens Prize, was won by a shooter using a rifle that had not been converted from a former service rifle; Geoff Cox shooting a Swing, a fellow club member when I shot with the RAF Target Rifle Club.

Now after the history lesson, I would expect that it would actually be necessary to have to alter slightly the tune of a barrel fitted with a tuner for different distances. I would not expect that tuner settings that provided minimum vertical dispersion at 50 m/yds would produce minimum vertical dispersion at 100 m/yds. As Mark (Patriot) says the point of minimum vertical dispersion for any particular distance is actually unlikely to be exactly at the node, so that the rifle will self compensate. If though you are in a position where you have to shoot at say both 50 and 100 without adjustment then the optimum tuner position will then likely be much closer to the node of vibration. Although this is unlikely to give the absolute smallest amount of vertical dispersion at either distance, it is likely to give the best combination of performance at BOTH distances. Given the ease with which tuners can now be adjusted, I'm sure that adjusting the fine tune between distances will become as common as adjusting the sights is now. So that the rifle can be shot with the optimum level of tuning at each distance.

Alan
Last edited by BigAl on Sat Jan 24, 2015 4:12 am, edited 1 time in total.
patriot
Posts: 272
Joined: Fri Jan 18, 2013 11:59 pm

Re: Tuners

Post by patriot »

Very interesting Alan; thanks for sharing. Shooting prone I tune for 100. The difference at 50 isn't as critical as the human pulling the trigger, at least with good ammo.

Mark
BigAl
Posts: 312
Joined: Mon Nov 26, 2007 5:37 am
Location: Norfolk England

Re: Tuners

Post by BigAl »

Mark, until now there have been a lot of prone/positional shooters that have not worried about tuners, even for those shooting on the ISSF 50m target and equivalents. For those shooters factory batch testing with quality match ammunition has been the answer, providing ammunition easily capable of holding the inner ten. Even at my relatively small club with about 20 active prone shooters three or four of them regularly batch test ammunition at the Eley factory. They are shooting in NSRA domestic competitions, although all NSRA rifle targets are proportional to the ISSF 50m target. Given that they have a rifle/ammunition combination capable of cleaning the target, with all inner tens, the efforts of setting up a tuner do not seem worth the effort in time/ammunition. Much better to expend that time/effort in improving technique and wind reading skills.

Now that the ISSF has introduced decimal scoring in all stages of the rifle matches though, we may well start to see those who have easy access to factory batch testing moving to using a tuner as well. For those shooters who are consistently keeping 98% (588) or 99% (594) or better of their shots in the 10 ring it becomes increasingly important to minimise the group size to maintain the decimal count. If any shot above 10.3 is down to statistical variation, and now that in all probability the number of shots that are in the 9 ring will be scoring high decimals the gap is suddenly much narrowed. At this point it may become a useful expenditure of effort to set up a tuner.

Mark as far as setting your tuner up at 100 yards, if I were going to pick one of 50/100 for setting up at I think I would also pick 100. After all it is unlikely that positive compensation at 100 yards is going to result in negative compensation at 50. If that situation were ever to arise I think that you would notice a sudden drop in performance at 50 compared to 100.

Alan
patriot
Posts: 272
Joined: Fri Jan 18, 2013 11:59 pm

Re: Tuners

Post by patriot »

Anything outside the X ring (10.4) is a miss.

I'm guessing a tuner set to 100 may have a slight over compensation at 50, which isn't really a problem in outdoor prone. In the big matches I burn good ammo so the tuner is less of a factor. In 2014 I lugged around two rifles. The prone iron sight is a 1913/2213 with a BeeSting tuner / bloop tube. The prone any sight is a nearly identical 1813/2213. The second rifle is slightly more inherently accurate, but is only tuned using receiver torque. Shooting the good stuff it does well. Shooting practice ammo it suffers a bit. (35+FPS ES or 7+ SD) The question is would adding the tuner to the 1813 for accuracy gain more than having something the wind can push around. But I'll probably add a BeeSting with a short tube. There is some conjecture that the tube allows the bullet to begin stabilizing before the wind can tip it; who knows.

Maybe someday I'll run the paper test to see where they go to sleep. Some believe the Eley EPS design has an advantage in this respect. Some also believe it has a BC disadvantage which hurts in the wind at 100. Some limited testing I did leaned that direction, but I really need a 100+ yard indoor range to take out the environmental factors. Lapua does seem to shoot better in windy conditions. Last weekend was warm and windy so I decided to burn up the Eley Edge I had tested that didn't have very good numbers. It shot surprisingly well in the wind; the last target 20X's windage. So now I'm curious if that coating is improving the BC (like a golf ball). Why would Eley have changed the coating? What was there reason for the added expense of another process? I wish I had paid more attention to the elevation change from 50 to 100, if I didn't miss count it was shooting high which would be another indication the BC improved. The next time I test ammo I may try to measure it.

The conformation that there is a forgiving tune node reduces my concern about testing ammo in a vice and not in the stock and in position. But I've heard the Eley test range will not share ammo ES and SD, unlike Lapua, so I won't go there. I also don't like that you may travel there only to find they have a limited supply of the lot your rifle likes. I wouldn't want to repeat the ammo search every year. Hopefully the distributor's quantities will increase to where we can once again order and test lots on our own.

Mark
Tim S
Posts: 2018
Joined: Mon Jan 03, 2011 11:33 am
Location: Taunton, Somerset

Re: Tuners

Post by Tim S »

Mark,

As I understand it Edge has the standard "black" bullet lubricant, like Club or Sport (Target in the US). It has the EPS bullet, but is made on the "black" bullet machinery, not the "white" Tenex/Match line. The black coating on the case is intended to replicate the better polish of Tenex/Match cases at a lower cost.
patriot
Posts: 272
Joined: Fri Jan 18, 2013 11:59 pm

Re: Tuners

Post by patriot »

Thanks for the insight. The Club I purchased in 2014 had shiny brass. Interesting what they want for a case of the Edge.

Mark
Tim S
Posts: 2018
Joined: Mon Jan 03, 2011 11:33 am
Location: Taunton, Somerset

Re: Tuners

Post by Tim S »

Yep, Club should have shiny brass. Edge has a coating that's meant to be an improvement on the standard finish, while less expensive to produce than whatever Tenex/Match cases get.
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