7.62 Gunner
Well-Known Member
Haha you really had we scratching my head with .236 erosion, even with N570
28 Nosler throat erosion 😳😳
- Thread starter Huntnful
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Yeah be some erorsion ,but I agree with RidgeReaper on your pic,Lots of bullet jump,more velocity.I think you got a false reading when you measured the first time.Using a bullet comparator on new berrel will do this.Tight,fresh cut chamber, throat,you've worn the new off,now it looks like your hitting the rifling,from the pic.The ogive on the HH bullets is way up towards the nose compared to the Absolute Hunters.I kept getting different reads with my 25 creedmoor, using the comparator and loading dummy rounds with the 121 HH,ended up using the 92 HH per call to Hammer. Call Hammer
Throated mine long. Shoots good. Just for hunting. Have other guns with same stock/scope set up for plinking.
177HH / 160 Accubond
177HH / 160 Accubond
shinbone
Well-Known Member
Whoever burns out the most barrels, wins.
MallardAddict
Well-Known Member
28's run on 570 kills barrels quick. I went through 2 28N barrels with 570 before I gave up a little speed and used Retumbo
Carey Farmer
Well-Known Member
Ditto. I burned up both a 28 Nosler barrel and a .264 Win Mag barrel before swearing off N570 and going back to Retumbo.
Very Hot burning powder.
Question: have you shot steel with a gun?
When the barrel is new, I use this method to help with the confusion. I will use the same bullet to measure the throat growth throughout the barrel's life. I put that bullet in a tiny plastic bag in the die box. Years ago, the gentleman that taught me this trick, taped the shot to the inside lid of the die box.
You need to measure the OAL to the lands with your intended use bullet.
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blackbrush1
Well-Known Member
I've also found 570 to be brutal. Try a 100gr pill in a 26 at 4000fps. Somewhat related, have any of you found the same to be true of 560? I would expect similar....
Carey Farmer
Well-Known Member
According to QuickLoad, N560 is in the same league as N570, even a little hotter. N560 heat of combustion is 4020 kJ/kg N570 is 3950. For comparison, Retumbo is 3710 kJ/kg; H1000 is 3630; US 869 is 3700.
From the wildcats and other overbored rifles i have used up. Retumbo and H1000 are good compromises between fps and barrel life . They have both gave me sub 1/2 moa .
the newest fastest cals wont support alot of load developement with 3-6 bullets and 4 powders , by the time your done the barrel is 2/3 -3/4 used up.
This id how i plan a new rebarrel , Pick a bullet ,have the smith chamber to that bullet or order a custom reamer to ur bullet and OAL specs . Pick two powders and ladder test them against each other come up with the oal thats hoots the best .
Run SD values for both. That should get you a good long range load and put 80-100 round count on barrel to achieve top speed .the next 20-50 rounds through rifle is to develop an accurate dope sheet .
125-150 total round ct and the rest of bbl life can be spent on putting meat on the table.
If a rifle ends up being a screamer, accuracy and fps wise, i also sometimes build a practice rifle on cheaper components to shoot alot and sacrifice the practice barrel instead of burning the top performing barrel up in a yr or two.
the newest fastest cals wont support alot of load developement with 3-6 bullets and 4 powders , by the time your done the barrel is 2/3 -3/4 used up.
This id how i plan a new rebarrel , Pick a bullet ,have the smith chamber to that bullet or order a custom reamer to ur bullet and OAL specs . Pick two powders and ladder test them against each other come up with the oal thats hoots the best .
Run SD values for both. That should get you a good long range load and put 80-100 round count on barrel to achieve top speed .the next 20-50 rounds through rifle is to develop an accurate dope sheet .
125-150 total round ct and the rest of bbl life can be spent on putting meat on the table.
If a rifle ends up being a screamer, accuracy and fps wise, i also sometimes build a practice rifle on cheaper components to shoot alot and sacrifice the practice barrel instead of burning the top performing barrel up in a yr or two.
550, 560, 570 are HOT!
There is a Heat Index Chart that is quite the eye-opener, powder listed from the coolest burning to the hottest burning
There is a Heat Index Chart that is quite the eye-opener, powder listed from the coolest burning to the hottest burning
How is the heat from the 1 series like 170, 160 etc.... The fps is just a little less.
160 is a very cool burning powder, very close to H1000. AA2700 is one of the coolest burning powders and it is in the burning rate of IMR 4350 approximately.
I think I am going back to the series 1 . Cheaper than the 5 series. Only loose a little fps with it. Thanks.
