Tikka .223 Rem velocity question

[JT27]

Had my T3X Varmint 223 out yesterday to chrono my Berger 80.5 load. I’ve been shooting this load for a little while now, mainly in a 300yd varmint match and it hammers. 23.9g Varget 205m 20 thou jump. Cleaned the rifle, shot 15 foulers and chrono’d the first 5. Surprised to see a 2604 avg, ES all over the place. The next 5 2594 avg ES 14 SD 6. Shot 5 more, 2598 avg ES 12 SD 5.

In comparison, my 77smk 24g Varget, 205M 20 thou jump, gets me 2801 avg.
I know I’m comparing two different bullets, and two slightly different weights, but what’s with the velocities on the Bergers?

This rifle takes a little more to foul in than others, hence the 15 foulers beforehand. But all 3 groups that I chrono’d were .4 and under. All my other loads for this rifle are getting me the velocities, or close to what I expect.

I don’t chase speed with my loads, so I guess it’s not that big of a deal. Just wanted to get an opinion(s) on why it’s so slow. Bearing surface on the Berger maybe?

 

[ShtrRdy]

I think it comes down to the sweet spot in the harmonics of the barrel.

 

[JEFFPPC]

I think it comes down to the sweet spot in the harmonics of the barrel.

What? Explain please.

 

[C.E.Smith043]

Had my T3X Varmint 223 out yesterday to chrono my Berger 80.5 load. I’ve been shooting this load for a little while now, mainly in a 300yd varmint match and it hammers. 23.9g Varget 205m 20 thou jump. Cleaned the rifle, shot 15 foulers and chrono’d the first 5. Surprised to see a 2604 avg, ES all over the place. The next 5 2594 avg ES 14 SD 6. Shot 5 more, 2598 avg ES 12 SD 5.

In comparison, my 77smk 24g Varget, 205M 20 thou jump, gets me 2801 avg.
I know I’m comparing two different bullets, and two slightly different weights, but what’s with the velocities on the Bergers?

This rifle takes a little more to foul in than others, hence the 15 foulers beforehand. But all 3 groups that I chrono’d were .4 and under. All my other loads for this rifle are getting me the velocities, or close to what I expect.

I don’t chase speed with my loads, so I guess it’s not that big of a deal. Just wanted to get an opinion(s) on why it’s so slow. Bearing surface on the Berger maybe?

I would say yes, the bearing surface is probably the difference.

You could also be losing some pressure because of the bullet jump for that particular bullet.

About the only thing I can think of you could try would be adjusting your seating depth and possibly Moly coating the bullets to try to gain some speed back and allow you to increase your powder charge a little bit

 

[K22]

I have the same rifle but shoot 60 Vmax with Varget. Accuracy is outstanding, in the .5's and .4's, at least for me.

Mine does not require any "fouling" shots since I do not use any aggressive copper removing solvents or procedures. I suspect that if you are aggressively removing copper down to bare metal, then the bore has to re-establish equilibrium before consistency returns. At least this has been my experience in the past.

However, the bullet could be the cause agent here. The bullet is the first place I look when developing a load and it goes sideways.

 

[JT27]

I’m scratching my head on how some of these guys on the Tikka forum are getting 2750+

I take the rifle down to bare metal every 300 rounds or so. I’m well aware of re-establishing the copper equilibrium. That’s why I shoot that many foulers.

I’m not saying there’s a problem, other than I was hoping my velocity would be more in line with some of the data I was referencing.

 

[ShtrRdy]

What? Explain please.

Okay, so the OP is getting 2600 fps with a 80.5 grain bullet load and 2800 fps with a 77 grain bullet load. The OP is wondering why the 80.5 grain bullet velocity isn't closer to the other one. When we find a load that puts the bullets close together on a target 100 yards or more downrange, it is because the barrel has reached a point in it's vibration cycle where it pauses for a moment as the bullet exits the muzzle.

 

[358WCF]

Had my T3X Varmint 223 out yesterday to chrono my Berger 80.5 load. I’ve been shooting this load for a little while now, mainly in a 300yd varmint match and it hammers. 23.9g Varget 205m 20 thou jump. Cleaned the rifle, shot 15 foulers and chrono’d the first 5. Surprised to see a 2604 avg, ES all over the place. The next 5 2594 avg ES 14 SD 6. Shot 5 more, 2598 avg ES 12 SD 5.

If I understand the above correctly, try firing the 1st 2 from clean without chrono, then resume (begin?) chronographing. The 1st shot or 2 always skews ES, which then skews SD. Around 20-40fps difference, or more, is not uncommon.

 

[JT27]

I should’ve worded it a little differently. I shot 15 foulers and then I began my chrono session.

 

[DLT]

I’m scratching my head on how some of these guys on the Tikka forum are getting 2750+

I take the rifle down to bare metal every 300 rounds or so. I’m well aware of re-establishing the copper equilibrium. That’s why I shoot that many foulers.

I’m not saying there’s a problem, other than I was hoping my velocity would be more in line with some of the data I was referencing.

My good buddy has a 223 tikka varmint he just did a load development with the 75eldm and varget. He’s at 2890. No signs of pressure

 

[LCazador]

I’m scratching my head on how some of these guys on the Tikka forum are getting 2750+

I take the rifle down to bare metal every 300 rounds or so. I’m well aware of re-establishing the copper equilibrium. That’s why I shoot that many foulers.

I’m not saying there’s a problem, other than I was hoping my velocity would be more in line with some of the data I was referencing.

I wouldn't worry about what others are seeing in their velocities. It isn't unusual to see a velocity variation as you're seeing between the 77g and 80g bullets. Frankly I find this is good. I wouldn't wait until 300 rounds down the bore to clean to bare metal. Are you cleaning the carbon ring after every shooting session? Are you using a bore scope and how did you establish this cleaning procedure. I'd be curious more as to why it's taking 15 rounds to foul. Have you tried starting the fouling process with your chronograph to see how the numbers compare during the fouling process to your record shots?

 

[Shutstr8r]

Not the same powder, but I shot an half gr over 24 gr of Ramshot Tac with the Berger 80.5’s and was getting 2800+ with a 24” barreled Remington 700. OAL was 2.50”. 23.9 seems a bit low to me with Varget. YMMV.

-Darrell

Ps- this was a load I used for 600 yd service rifle in a gas gun before using it in my bolt gun. It was an AMU load.

 

[JEFFPPC]

K he wantedOkay, so the OP is getting 2600 fps with a 80.5 grain bullet load and 2800 fps with a 77 grain bullet load. The OP is wondering why the 80.5 grain bullet velocity isn't closer to the other one. When we find a load that puts the bullets close together on a target 100 yards or more downrange, it is because the barrel has reached a point in it's vibration cycle where it pauses for a moment as the bullet exits the muzzle.

Your right about the harmonics.....I had a tuner for years when no else had one except for one guy, the others laughed. Now most of them have tuners, I laugh at them. Yes velocity plays a part in where the barrel is when the bullet exits but his question is about what is affecting velocity . I don't think barrel harmonics have anything to do with determining velocity. You are correct that velocity does effect harmonics from the point of out where the bullet exits the barrel. It's a case of spending time on something with no bearing on performance, but many go down these paths for reasons that never compute with me.

 

[JT27]

I wouldn't worry about what others are seeing in their velocities. It isn't unusual to see a velocity variation as you're seeing between the 77g and 80g bullets. Frankly I find this is good. I wouldn't wait until 300 rounds down the bore to clean to bare metal. Are you cleaning the carbon ring after every shooting session? Are you using a bore scope and how did you establish this cleaning procedure. I'd be curious more as to why it's taking 15 rounds to foul. Have you tried starting the fouling process with your chronograph to see how the numbers compare during the fouling process to your record shots?

I wait to clean for 300 rounds or so because my accuracy is holding. I do clean the carbon ring after every outing and checked with my borescope. The rifle has always taken a few more shots than ”normal“ to foul back in. I ran 15 through it just to be sure when I started my session.

This was my initial work up for this load. Barrel had about 200 rounds on it. 5 shot groups.

 

[LCazador]

Whats barrel length? Have you tried anything besides Varget? Did you do any work seating a bit closer to the lands? One powder doesn't make a rifle!

 

[JT27]

Whats barrel length? Have you tried anything besides Varget? Did you do any work seating a bit closer to the lands? One powder doesn't make a rifle!

Factory 23.6in barrel. Haven’t tried anything other than Varget with the 80.5’s. I tested .030, .020, .010 and touch for seating. Didn’t see any noticeable difference except when touching. Settled on .020 jump.

I’m more than happy with the load that I have. Didn’t feel the need to pursue any further. Consistent .3’s @100 with the occasional .2. @300 getting .7 to 1.2’s pretty consistent in mild conditions. For a weekend hacker like myself and a factory rifle I’m content.

Was hoping for more insight on why the velocity drop on this bullet. Like I said, I don’t chase speed when developing loads so it is what it is.

 

[LCazador]

You may want to try a different powder to see if you get the same velocity issues.

 

[DLT]

Factory 23.6in barrel. Haven’t tried anything other than Varget with the 80.5’s. I tested .030, .020, .010 and touch for seating. Didn’t see any noticeable difference except when touching. Settled on .020 jump.

I’m more than happy with the load that I have. Didn’t feel the need to pursue any further. Consistent .3’s @100 with the occasional .2. @300 getting .7 to 1.2’s pretty consistent in mild conditions. For a weekend hacker like myself and a factory rifle I’m content.

Was hoping for more insight on why the velocity drop on this bullet. Like I said, I don’t chase speed when developing loads so it is what it is.View attachment 1629818

What miter saw stand is that ?? I have got to get me one like that

 

[JT27]

Menards.
I used T-nuts to hold the brackets to the 2x4s so I could remove them and use them with my saw. Or you could order another set of brackets, if you had use for a miter saw stand.

 

[Chestnut]

What miter saw stand is that ?? I have got to get me one like that

It's similar to the Ryobi miter saw stand, in the event that you don't live near a Menards. I just made a table the exact same way.