3 groove Barrels

[Fiftydriver]

JE Custom,

For your application, if I were doing something like this, I would go with the Ballistic tips first and formost.

In my 22-6mm AI, I am driving the 50 gr Blitzking to 4200 fps and they work fine. I drove the 40 gr BK to 4400 fps but they turned to dust. This is out of a 1-14 twist 6 groove barrel.

Changing to the Ballistic tips, I can drive a 40 gr as hard as I possibly can and it will not show any sign of a problem with this velocity and will take an rifling design you want to use it in and behave perfectly well.

 

[ss7mm]

Shooting the 200 gr ULD RBBT from wildcat bullets using the J-4 jacket, they would shoot great to start with and then the bullets would start coming apart and eventually every one shot, no matter the velocity used would tear the bullets apart.

BTDT Sounded like a cross between a whiffle ball and a small helicopter at times.

One of them even took out a leg on a skyscreen.

 

[royinidaho]

Not intending to high jack, but what kind of jacket is needed for the Lilja and original Rock 3 groovers?

 

[jwp475]

Not intending to high jack, but what kind of jacket is needed for the Lilja and original Rock 3 groovers?

A strong one..

 

[ss7mm]

Not intending to high jack, but what kind of jacket is needed for the Lilja and original Rock 3 groovers?

Can you say "Accubond"???

 

[royinidaho]

yehbut, a 140gr accubond is peckerwood and the 150s are ballistic tip but'll do the job on muleys.

 

[ss7mm]

Yup

 

[MagMan]

Here's part of a 200 RBBT from the 7 twist 3 groove days.

 

[uncleB]

- Barrel life is longer. Roughly 15-18% longer compared to a traditional 6 groove barrel. Roughly 10-12% longer then 5 groove barrels and around 8-10% longer then 4 groove. That being all barrels made from the same material and hardness.



I agree with everything that Fiftydriver said except this quote, I dont think you can put a blanket statement down on how much longer a 3 groove will last.
While I hope my 222Rem 3 groove will last 15-18% longer than it's 6 groove counterpart, I guarantee that my 6-284 3 groove went away 50% faster than the previous 6 groove that was on it.
With firebreathing rounds such as a 6-284 the throat will firecrack before it starts to erode forward and bullet blow-up will occur hundreds if not thousand's of rounds sooner.

A 3 groove barrel is EXACTLY like getting married to a woman with no moral values, it is wonderful and exciting in the short term but in the long run is more disappointing than you will ever imagine. I have more experience with both than I care to admit and both are of the Devil and to be avoided for the rest of my life !!!!!!!!!!!!!!
UB

 

[Fiftydriver]

Uncle B,

THose numbers were just rough estimates from what I have seen comparing a dozen or so 3 groove barrels with a like number of other rifling designs. As always there are variations that will effect a specific barrels accuracy life.

In your example, I would say I have seen similiar results. I have a 6mm-284, 30" 1-8, 3 groove barrel. The rifle has +1200 rounds down it. It has severe heat cracking in the throat as well. I do not shoot Berger bullets out of it, I shoot the 107 gr SMK.

In its early like, first 400-500 rounds I was pushing the 107 gr SMK very hard, +3550 fps. Since then I have tamed her down to 3400 fps. I have used the rifle for long range varmint hunting for over 10 years now and it will still shoot the 107 into sub 3/4 moa out to 1000 yards if I do my part in good conditions.

If I were shooting the Berger bullets, I am sure my results would be exactly what you are seeing. I do not know what bullets your using but in my 3 groove, the Berger 105 gr VLD or A-Max 105 shot EXTREMELY well until velocity reached 3250 fps. They shot even better then the 107 gr SMK but I wanted more velocity so I switched to the 107 gr SMK which still shot very well.

I have yet to have a SMK come apart at 3400-3450 fps.

I have also gone to great care not to over heat that barrel. To the best of my knowledge, I have never sent more then three rounds down that barrel in a string for its entire life. I am sure there have been a few longer strings but I can not remember it.

As such, I am sure that has come to the long life with this barrel.

Again, all my comments were just a general comparision for what I have seen with my different test barrels over the years.

 

[uncleB]

Kirby,
I hope you know that I was not trying to dis you in any way you are my friend, my point is that a 3groove is FOOL'S GOLD.
It sound's great but reality is completely different from the media hype.
The two biggest 3 groove barrel manufacturers are Pac-Nor and Lilja, they sell you on the false advantages of the 3 groove but never tell you the dis-advantage's.
My intent is to try and keep innocent victims from making the same mistakes that I have, Lilja and Pac-Nor both make great barrel's but they have more groove's than 3.
UB

 

[Fiftydriver]

Uncle B,

Certainly not offended in any way. I agree with most of what you say. If someone is using a fast twist barrel with a thin jacketed bullet, the 3 groove will cause all kinds of trouble just as you discribe.

The harder the bullet, the less effect you will see because of the wide lands.

I had 8 customers shooting my 7mm AM with these three groove barrels that started to have problems exactly as you discribe. While we were waiting for the barrels that I would replace their three grooves with, I recommended they use the 160 gr Accubond to get them through that upcoming big game season.

So in my opinion, if your shooting thin jacketed match bullets, you will certainly have problems down the road with the 3 groove exactly as you discribe. If you use a moderately thick jacket such as with the SMK, it can be a way to increase usible barrel life and if you use a stout bullet such as a Ballistic Tip or Accubond I seen nothing really wrong with the 3 grooves.

Also, the effects of the 3 groove barrel are exaggerated the faster the twist rate.

I seldom use the 3 groove anymore in anything except my 270 AM wildcats. The vast majority of barrels are now 4 or 6 groove barrels but have no problem with a properly designed 5 groove for the bullet application at hand.

Again, no offense taken at all. If my reply seemed as though I was a bit miffed, I apologize for that sincerely, not my intention in any way because for the most part I agree with your comments. For thin jacketed match bullets, I agree 100%.

 

[J E Custom]

This has been a very informative post and I really appreciate all of the
responses !!!!!

Right now it looks almost like a draw on likes and dislikes 55% for and 45%
against but I'm hoping I am one of the lucky ones that has no problems.

I did notice most were using the fast twist 3 groove barrels and I went with
the 1 in 15 twist because of velocity ( my 22-250 had a 1 in 14 twist and
it performed great) so maybe I won't have the same issues with jacket
separations.

I will also try the 40gr Ballistic Tip as you suggested Kirby ,and will let everyone
know the results after testing and if it all goes bad I will post all the results
good and bad.

Only time will tell on barrel life. I will follow a proven break in procedure and
give it every chance .

Thanks again, any more comments?
J E CUSTOM

 

[Fiftydriver]

The slow twist and heavy based bullet will help you alot, you should not see many of the issues we are discussing with the 3 groove barrels with that combo. As you said, time will tell on barrel life but with that bullet you should get as much as possible out of the combo.

Keep us posted.

One question, what will you be using this rifle for? Just curious.