Timo on expertistä kaukana,mutta Frank Greeniä voitaneen pitää experttinä.Oli Kriegerillä töissä,kunnes perusti Tracy Bartleinin kanssa Bartleinin piipputehtaan.
Kun häneltä on kysytty mikä rihlojen määrä on paras,hän on vastannut alla olevan tekstin:
Jos tuosta yrittää kaivaa lyhennelmän,niin:
*Hyvin käyviä piippuja on tehty 2/3/4/5/6 palkkisena
*99 % lyhyen matkan kasa-ammunnassa on 4-rihlaisia.
*Pitkän matkan ampujat mieltyneet 5 R rihlaukseen (Tuolla perusteella valitsin oman Border piipun 5R rihlauksella)
Hiukan omaa vatulointiani tähän perään:
*Rihlapalkkien leveyden suhde uriin?
*Rihlapalkkien korkeus?
Ilmeisesti nuokaan ei ole ratkaisevia,JOS piippu on ABSOLUUTTISEN homogeeninen mitoiltaan/palkeiltaan/uriltaan.
PPC luoti pyörii n.2800 r/s.Piekkarin luoti n.800 r/s.
Jos yksikin ura on hiukankaan syvempi aiheuttaa se vipatusta luotiin.
Olen hiukan sarkastisesti ajatellut kun piekkareissa nuo MI (Mini Invasive) piiput = matalapalkkiset ovat osoittautuneet käynniltään ja tuulen vienniltään erinomaisiksi.
Jos työstövirheet ovat PROSENTEISSA yhtä suuria,niin matalapalkkinen on TUHANNES osissa pienempi virheeltään ja aiheuttaa pienemmän vipatuksen / pienemmän "tuulipussin" luodille-
.
*Se on kuitenkin tutkittua tietoa,että jos huippupiipussa on lämpökäsittely ja piipun sisämitat viimeisen päälle,niin TASAINEN RIHLAN NOUSU koko piipun matkalla on se TÄRKEIN tekijä huippukäynnille.
Ei siis saa olla jostakin kohdasta 13,4 " ja jostakin 13,6 " vaan koko matkalta 13,5 ".
Gain Twistissäkin rihlannousun kiristyminen TASAISESTI suuta kohti.
*Tuosta tähtikuviosta? Piipussa tapahtuu ainakin 9 eri taajuista värähtelyä ja osa on pysty värähtelyä,mutta myös kiertovärähtelyä.
Värähtelyn kulkunopeus piipussa on jopa 5000 m/s eli se ehtii kulkea monta kertaa edestakaisin vrt.luodin nopeuteen.
On vaan haettava luodille oikeaa nopeutta,jotta se irtoaisi piipun suulta optimaalisella väräyksen hetkellä.
Tuohon väräykseen vaikuttaa iskurin lyönti,luodin nopeus,luodin asetussyvyys,hylsyn suun kovuus,jne.
Tuotahan kasa-ammunta on. Ikuista huippu tuninkin metsästystä VALLITSEVIIN OLOSUHTEISIIN.
The number of grooves? To me the number of grooves has no real bearing on accuracy or barrel life! Some say if you want hard core accuracy go with conventional rifling vs. 5R type rifled barrel. Some say the 5R's copper foul less. I say B.S. I've seen 5R's copper foul with the best of them. Some say the 5R barrels will seal the bullet better in the bore and you get more velocity out of them. Again I haven't seen this either. Some say the 5R barrels don't leave a burr on the bullet and the bullet will drift less in the wind. I haven't seen this either.
99% of the barrels we make for short range bench shooters are 4 groove conventional rifling.
Across the course high powers shooters seems to be a 50/50 split.
Long range prone shooters seem to prefer the 5R.
Long range bench shooters I would say the preference is towards conventional rifling.
I've got a conventional 5 groove,not 5R) on my short range bench gun. Wanted to try it! The gun hammers!
I've shot 5R and a 4 groove in prone matches out to a 1000 and even compared both in the same match,two man team) and saw no difference. Our team came in 3rd for points. Same chambers, same loads! Both guns we're chambered in 6mm Rem. with a custom throat. In that match we shot 107 Sierra's,I've shot mostly Berger 105's after that). Both are 1-8 twist barrels. Velocity difference between the two was 30fps. The loads average 3155fps. between the two. We didn't use anymore or any less windage on one gun vs. the other!
Some will say the odd number of grooves will help with jacket failure? This is because the odd number of grooves vs. an even groove barrel will distort or upset the bullet jacket less. This is because the lands don't directly oppose one another. I believe this has some merit but it is hard to prove. Read the next paragraph though.
I compared a 5R and a 4 groove in the match at a 1000yds. the match I mentioned earlier. The 4 groove was the second barrel in a row that I had when I was at Krieger that would blow up one manufacturers bullets but not another. I stopped shooting them for awhile because I was to scared to use them.,Who the bullet makers are is not important. I still shoot they're bullets!) So I wanted to see what would happen. Bought some more of those one makers bullets and guess what. No failures in either one. So in away that kinda blows the theory!?
Both barrels we're made to the same bore and groove size and same twist. Same chamber and the same loads shot thru them. Why didn't the one barrel blow up anymore of the one makers bullets anymore? I chalk it up to a different lot. Maybe the lot of bullets I got had problems with the cores or jackets? Hard to say!
Barrel life? Again I don't see a difference in the number of grooves effecting barrel life etc...One barrel maker who is making 3 groove barrels the last I heard was claiming they last longer. This might be true in a button rifled barrel because of the wider lands. On average I don't see a button rifled barrel lasting as long as a cut rifled barrel. Why?
Because the button rifling operation work hardens the bore. I'm not saying a button barrel will not go a long time or a cut barrel will not burn out early as I've seen both. It's just what we see as an average. Can I put a number on it. Not really but if I had to I would say about 20% longer on cut barrels but this all depends on the accuracy level each individual shooter wants/needs, how good they are not to mention a whole ton of other variables that effect barrel life. One guy shoots a powder that is more abrasive than another is an example. Not to mention the steel from one lot to another even if you are getting the steel from the same supplier can be a variable. The list doesn't stop almost.
When we we're at Krieger back around 2000 Tracy made the tooling for a 3 groove .30cal. palma barrels and we made a couple for Mid Tompkins. Mid told me that accuracy wise out to 800 yards they shot just fine compared to the 4 grooves. The only problem was both barrels we're a flat 100-150fps. slower than the 4 grooves so they wouldn't cut it at 900 and a 1000 yards. due to the velocity loss. Why? Maybe because of the wider lands? Different lot of steel? Hard to say sometimes but that is my guess the wider lands.
Also at Krieger right before we we're gone from they're we made a cut rifled barrel and a button rifled barrel in .224 cal. for John. He chambered them up in .22-250 and put them on some prairie dog guns that he took out west. They we're made out of the same lot of steel and got the same loads thru them. Accruacy wise both shot great but the button barrel was exhibiting more wear with the same round count on both. Both barrels we're being shot in the same conditions and the same loads we're being put thru them.
I've seen 2 groove, 3's, 4's, 5's,5R's) and 6 groove barrels all shoot excellent. So again I say there is no difference in in accuracy or barrel life but when you compare one or the other you should be comparing/testing the barrels made out of the same lot of steel and being made from the same maker and being shot in the same conditions. This is the only way to get good results but who has the time, money etc...to do this? This is the hard part.
Check out the thread records fall at Sacramento. Craig St.Clair shot a 1-8 twist, 4 groove, .237 bore at 600 yards chambered in 6BR. He won 7 out of 8 awards and has 2 pending records. It was smithed by Stu Harvey.
In the end to me it is more of the quality of the barrel blank. The straighter the barrel, the more uniform the bore and groove dimensions, and the more uniform the twist the more forgiving the barrel is going to be. The nicer the finish inside the less fouling it will have etc....
Keep in mind there are alot of variables beyond the barrel maker and gunsmiths control and even the shooters control. What chamber reamer was used. Different lot of bullets from one to the next, different lot of powders, primers, cases etc...all effect different things. Why is one barrel faster than one vs. another. Why does one barrel that looks glassy smooth foul bad and it shouldn't etc................
Talk to you all later, Frank @ Bartlein Barrels
