Issue with 4th+ round fliers

[JARHEAD1371]

Have you tried a different primer. Just analyzing but your groups aren't shooting in the same spot. 1/2" here 1/4" there. Just doesn't seem like a solid load. What are your velocities and spreads like?

I have about 1500 BR2 primers, but none others. I'll try others when I can find them.

 

[LVJ76]

Or looking through heat waves coming off the barrel.

To be honest, I hardly ever (99.8% of the time) shoot 5 shots in a row, and definitely not in 90 seconds. And not with a laser beam load like a 25SST with 60ish gr of powder at 3100+fps.

You already know it shoots 3 in a row well, then letting it cool keeps the group tight. Not sure why you keep shooting 5 in a row with the same results.

As Lance said, on magnum velocity cartridges the barrel will heat up faster causing flyers on the 4th or 5th shot, its normal.

Stay safe

 

[Tiny Tim]

Most of us wouldn't shoot 5 shots in 90 seconds unless it was a comp gun. If its consistently throwing the shots beyond the third without a cooling off period, its a heat buildup issue. 25 SST is a hot one and as others have stated, a carbon wrapped barrel is a smallish diameter steel barrel "liner" that will heat quickly internally while seemingly cool on the outside.

 

[30calyooper]

Semper Fi Brother! (USMC 81-88, Recon Marine)

Barrel cooling issue. Ever try the trick of timing your shot intervals? Bet a dollar the longer you wait the lower you dispersion especially for shots #4 and #5.

Heating can also effect the bedding, especially if you have a fully-bedded barrel vice a free-floated tube. No way around pure physics! You might not inherently think of this, but anyone who has shot more than 2 rounds in succession out of a launcher in a cheesy ramline plastic stock can tell tell you how much they start to fly!

 

[Rardoin]

First rule out the 600lb gorilla in the corner.... Does it do this when another solid shooter fires a 5 shot group with the same gun/load? I have had issues similar in hunting rifles years back and my father would try to duplicate it and wouldn't ya know it....all 5 in group. Flash forward to current times... I shoot F-open off a very solid and well tracking rest/bag/1.8oz trigger and occasionally I have the 4 in, one out syndrome. If I relax, focus on the aim point and fire each shot more slowly in a cadence my shots all go in group (provided my load is correct). Setting the scope a minute high or low to not adulter the aim point/distract from the aim point can also help tighten groups IME. I don't intend to doubt your skills but sometimes I get rushed and don't focus as well on the 4th or 5th shot in a test group.

 

[Deviant]

I'm working up a load for my new 25 SST, H1000, BR2, and the Blackjack 131. I'll shoot 5 shot groups and always have shots 4 and 5 as fliers. All 5 shots are in about 90 seconds.

If I shoot 3 in about a min, then wait for about 10 min, and shoot 2 more, then they all group together tightly.

I've never come across this situation and I appreciate any shared info. My barrel is a CarbonSix 7 tw and 24" long.

5 shots in 90 seconds with a barrel burner? Be nice to that poor barrel so it lasts more than 500 rounds. I would guess its your barrel heating up and the first shot is all that really matters. I typically shoot cold bore groups to make sure that 1st shot is always where its supposed to be. Then I will shoot two in a row just to be sure my follow up shot will hit its mark as well but I never shoot more than two consecutive shots without letting the barrel cool because I don't like buying $800 proof barrels and redoing load development very often. I'm not saying that what I do is right but Ican guarantee that if you shoot 5 in a row with a laser that you are inducing premature throat erosion and fire cracking. Just my humble opinion so take it for what its worth but it sounds like you have a great shooter.

 

[25WSM]

Barrels are like underwear. If they get crappy change them. I have one life to live I'm not wasting it on waiting for my barrel to cool between shots. Let it rip.
And then let it R.I.P. they are making new barrels every day. Today its harder to find enough components to shoot a barrel out.
Shep

 

[Korhil78]

I don't see why others are recommending trying different things when he said in his post that when he shoots all 5 shots in 90 seconds that it shoots shot 4 and 5 out. But when he takes longer and lets the barrel cool, it shoots them all together.

It's obviously the barrel heating up and stringing the shots.

 

[25WSM]

Yes it's heating up and moving his impact point. But sometimes it's not entirely the barrels fault. Suggestions have been made to try and help the problem. A barrel that does this can almost always be made to shoot better with a pressure point. I've seen where the barrel channel was just slightly close enough to the barrel that it would start touching. Then they really move. And if you have a bad bedding job a little heat in the front of the action around the chamber can wreak havok. So suggestions have been made to try and help that's what we do on this site is try and help each other. I've been smithing for over 30 yrs and have seen it all for the most part. Some things can be helped some not so much but you won't know till you find solutions and try them. It will never be a waste of my time trying to help a member out.
By the way to the op if you do a pressure point you will most likely need to retune your load some. Your barrel will act like it's half as long. This is why so many factory rifles came with a pressure point. Factory barrels are not stress relieved perfectly if at all and most have no bedding. Good luck.
Shep

 

[WILLIAM E YOCKEY]

Or looking through heat waves coming off the barrel.

To be honest, I hardly ever (99.8% of the time) shoot 5 shots in a row, and definitely not in 90 seconds. And not with a laser beam load like a 25SST with 60ish gr of powder at 3100+fps.

You already know it shoots 3 in a row well, then letting it cool keeps the group tight. Not sure why you keep shooting 5 in a row with the same results.

Could've said it better

 

[lancetkenyon]

Could've said it better

Then say it better!

 

[Korhil78]

Yes it's heating up and moving his impact point. But sometimes it's not entirely the barrels fault. Suggestions have been made to try and help the problem. A barrel that does this can almost always be made to shoot better with a pressure point. I've seen where the barrel channel was just slightly close enough to the barrel that it would start touching. Then they really move. And if you have a bad bedding job a little heat in the front of the action around the chamber can wreak havok. So suggestions have been made to try and help that's what we do on this site is try and help each other. I've been smithing for over 30 yrs and have seen it all for the most part. Some things can be helped some not so much but you won't know till you find solutions and try them. It will never be a waste of my time trying to help a member out.
By the way to the op if you do a pressure point you will most likely need to retune your load some. Your barrel will act like it's half as long. This is why so many factory rifles came with a pressure point. Factory barrels are not stress relieved perfectly if at all and most have no bedding. Good luck.
Shep

Totally understand what you were trying to do with your suggestions as your suggestions related to the barrel heating up and how to alleviate through other means of correction such as pressure points etc. I meant the load development and having others shoot the rifle. Should have been more specific. And yes I agree about this site being great about helping others. Maybe I'm just being grouchy today haha.

 

[Tulsa Reiner]

90 seconds is longer than you think, and probably shorter than I typically shoot the 5 rounds. If a barrel beats up that fast, than it's not worth having IMO. While a one shot kill is ideal, sometimes this doesn't work out. Besides, if you shoot any type of PRS type matches then you are screwed. I sprecken the 25 SST is a hotter round than you typically see at a match, but 3 rounds is several less than it should be for this situation.

Remember that although a CF barrel is cooler that steel on the outside, it experiences the same heat on the inside, and is slower than steel to dissipate it. I allow 2 full minutes between shots for a 5 shot string from my CF barrels.
That may be more than necessary, but I don't experience what you're getting.
It wouldn't hurt to wait longer between shots, just to see if that cures the problem.