This Hawk Hill 6.5cm barrel will probably be the first barrel I shoot out. Im approaching 500 rounds. At want point (aprox) do you start seeing throat erosion and start having to chase the lands to maintain bullet jump.
How many rounds until you start seeing throat erosion
- Thread starter LC 6.5 Shooter
- Start date
Technically every shot down the pipe causes erosion. You need to track it. I track every 250-300 rounds to keep my load in tune.
Thanks. Thats what I was looking for. Ive got right at 500. Ill check it today and see how much it has changed so far. Only problem is Im right at mag length with the 147’s with 0.060” jump.
I think aics but they allhave the plate in them. Tried to drill one out. Didnt go well...$70 gone. F’d it up good lol.
Yeah, switch to non binder plate if it’s a custom action. Also why are your shooting 147’s? What is this rifle used for?
Yes custom rifle. Mpa chassis. Curtis Axiom. Trigger tech special. HH 26” spun by pva, 419 hellfire brake. I was shooting 140’s and tried the 147’s and the gun really liked them. I tried some 130 berger ar hybrids but it shot the elds better. Overall goal is to get into some local prs matches and Long range shooting. My deer lease is by CCC in navasota texas which runs prs events etc.
Throat erosion is not linear. The average in my barrels has worked out to 0.002 - 0.003 per hundred rounds but there are several factors involved; powder used, hot load, running the gun hard, etc.. all of which can change the dynamics. I typically shoot bullets that can handle jump so erosion is less evident in terms of accuracy. If I see loss in velocity but accuracy is still there, I change my ballistics program and carry on. If I see a loss in accuracy and speed, I’ll re-work the load and find another accuracy node knowing that I may or may not get the speed back. Makes no difference to me: accuracy trumps speed every time.
There are some bullets out there that you really don't have to chase your lands with, hybrids come to mind. I have no history with your bullet, but I would wait till you see accuracy degradation before I did anything. And only you can judge when that time is. I'll usually shoot the same load till I experience a pressure dump(velocity loss) caused by throat erosion, then try adding powder, switching powder, etc... I really haven't had much luck chasing the lands with a worn out throat. But I am shooting a 6mm 110 Sierra exclusively right now and may have to re-educate myself soon.
By all means look for a non binder mag, Accurate makes 10rdr's, AI has a 5 rd, not sure on 10.
By all means look for a non binder mag, Accurate makes 10rdr's, AI has a 5 rd, not sure on 10.
I would recommend running the accurate mags without binderplate. Also, I think it would be good for you to try the 130 class bullets. Will gain you more mag space and less recoil (very important in PRS). I’m surprised your gun doesn’t like 130 hybrids, wpuld be the first I have ever seen that didn’t. Try jumping them 15 thow. Of course there are a lot of factors in erosion, that being said, they ALL erode and need to be tracked. Are you using a chrono to find nodes, than loading in the node?
Thanks for that, I was in a thread on here and a guy was saying .004" erosion was huge, your findings mirror mine.
I'm curious how you figure a 130gr bullet is going to reduce his recoil so much he will actually notice the benefits. Most likely he will add more powder to the case.
I messed around with a 130gr Norma in one of my 6.5 creeds a few yrs ago, I do not recall a benefit one from doing so.
Just how it works. Lighter bullet will give less recoil in actual practice. Been shooting 6.5 for a while. The 130’s are noticeably lighter recoiling than 140’s. Same reason a lot of people shoot 105 6mm over 115’s.
I understand the principle fully, I myself did not see it. Most factory 124gr 9mm loads are easier to handle than the 115gr loads, shooting a sub 147gr is powder puff league. Step up to a 45acp with 200gr and 230's, and now my theory falls flat.
There is no use telling the op to change what he is doing, let him toast this barrel and then make some decisions. If he is shooting prs, he is most likely getting a serious education and probably won't rebarrel to the 6.5 creed again.
It’s my opinion the lighter projo will yield less recoil. I shoot 6.5 in prs and so do MANY successful shooters. Given he said he is planning on shooting prs, why not help him be successful. If he wants to shoot 147’s that’s his call. I would put money he is the only guy on the line shooting 147’s. Lots of guys running 130-140 class bullets in 6.5. I understand your point about pistols and recoil. All the same principals apply, just like you said. Prs is a game of fast target acquisition with follow up shots and spotting impacts to make corrections. Less recoil buys you points. Since he is constrained to 6.5cm my logic says “shoot the most applicable bullet for your application”. Your expirence didn’t lead you to a conclusion most people have, lighter bullet is less recoil. In prs, it all adds up.
Two erosion extremes.
The 6.5 throat burned up quick where the 5.56 shows no measurable erosion.
Although I measure the throat on the 5.56 with a 53 gr sierra I shoot 77gr SMK.
Factory 6.5 creed
Sinclair gauge 140 ELDM CBTO
2.225 NEW
2.243 (868)
2.253 (1208)
2.267 (1386)
2.280 (1870)
5.56 Gas Gun
Kreiger Barrel
Sinclair gauge 53gr SFB CBTO
1.864 New
1.864 (602)
1.864 (1130)
The 6.5 throat burned up quick where the 5.56 shows no measurable erosion.
Although I measure the throat on the 5.56 with a 53 gr sierra I shoot 77gr SMK.
Factory 6.5 creed
Sinclair gauge 140 ELDM CBTO
2.225 NEW
2.243 (868)
2.253 (1208)
2.267 (1386)
2.280 (1870)
5.56 Gas Gun
Kreiger Barrel
Sinclair gauge 53gr SFB CBTO
1.864 New
1.864 (602)
1.864 (1130)
Accuracy is fine velocity took a dive.
I am running a new lot of H4350, even with a increased charge of 1.0 grain I still was 45fps slower so I switched to R16 and speed is back.
Hoping to get another 300 rounds out of the barrel then it will owe me nothing.
If I would of let the barrel cool longer between strings it would have eroded less, but chit happens.
I am running a new lot of H4350, even with a increased charge of 1.0 grain I still was 45fps slower so I switched to R16 and speed is back.
Hoping to get another 300 rounds out of the barrel then it will owe me nothing.
If I would of let the barrel cool longer between strings it would have eroded less, but chit happens.
Savage 12FV now with 2700+ rounds down barrel. Shooting 90% Hornady 147 eld-m and RL16 my gun eroded .050 per 1000 rounds.
Now I'm about .130 forward at 2700. Still shoots 1/2 MOA Velocity is down about 50-70 from eariler readings. I don't chase the lands.
Never would of thought the gun would still shoot this good with this many rounds. HB
Now I'm about .130 forward at 2700. Still shoots 1/2 MOA Velocity is down about 50-70 from eariler readings. I don't chase the lands.
Never would of thought the gun would still shoot this good with this many rounds. HB
I had 7 130 hybrids left so I loaded them up with 44g of Rl16. My original testing was done at 0.010” jump. However I seated them right were my micrometer was set for the 147g elds thinking I would have to go deeper. Well that ended up being 0.040” jump (probably more with throat erosion from original measurements). SonI said screw it and loded all seven there. Shot fantastic. Shot 4 at 100yds (.26” group) and 3 at 300 yds (1.20” group). 7 shots mv-2958 es-7 sd-3.1. Might have to revisit them lol. Only problem is I have 1200 147g elds.
