Home Forums Hunting & Shooting Ask The Gunwriters Barrel twist....riddle me this

I'm a hobbiest gunsmith on my personal collection who quit doing public work a decade ago. I've spun a lot of barrels on from most makers and refits between manufacturers.

All of my experiences have shown me that in 30 plus 10 twist 30 cal rifles at my elevation of 3k-ish feet that there's no issue with stabilization in 200-215 class bullets, at least from berger, horn and sierra.

Last month I built myself 3 rifles all 10 twist, 2 in 300wsm 1 in 300win. The WSM's are a 21" proof stainless on a win classic and a 24" lilja on a sako av. The 300win is a push feed. All 3 are bedded similarly, all floated to at least 20mil and all wear mcmillan stocks. All wear quality, proven scopes in quality proven mounts. By proven, I have shot them personally as well as attached an indicator to the scope and action to measure movement between them.

Every screw is dyed and measured to ensure zero contact and in the case of the 300win, it wears 8-40 and bedded (grit blasted contact points) pic rail....its solid.

The two 300wsm's are boringly accurate and will shoot one hole groups with their best loads and about an inch and a quarter with their worst.

The 300win is my anomaly. I fired it up on the first day with a shoot, clean shoot rotation for 5 rounds and it wasn't pretty, but I hadn't yet shot 3 or more in a row.....when I did so with a charge of h1000 pushing a berger 200.20x my groups were barely staying on a piece of butcher paper.

I immediately assumed the scope it wore was junk and replaced it with a new lrhs and loaded a ladder based on my other 300win successes. The lrhs shot equally poor. I had questioned on of the base screws upon assembly so it was at this point that I took it to 8-40 and bedded the rail.....no change.

With 40 rounds and no two landing within 4" of each other I pulled another lrhs from a very lightweight 300rum that's been very accurate for me tho eliminate the possibility of 2 bum scopes.

Scope 3 shot similarly. Up to this point I've taken h1000 and h4831 from 2700 to 3k fps and from a kiss to .200" off with berger 200.20x, 208eldm and 210 accubonds.

Cleaning, scoping and checking my work has me head scratching. I load up some 165, 175 and 180's....suddenly I can't shoot over an inch. The gun is absolutely what I expect from bartlein....but only to the 180 class.

Checking twist has been a bit inconsistent in my findings but it sure isn't a 14 twist.

I called bartlein and they told me not to expect their 10 twist to stabilize a 200.20x. This threw me for a loop. If every other maker's tube works....why not a bartlein?

My question to you is have you found that a 8 or 9 is required for stabilization of 200 plus class pills?

It doesn’t sound like a stability issue to me.

Which model of lighter-weight bullets did you get to shoot well?

https://bergerbullets.com/twist-rate-calculator/

175 rdf, 180 sierra game kings from the 70's and 180 ab.

I’m not sure exactly how all the jackets compare, but I’m curious if the rifling profile is deforming the Bergers excessively, which could lead to bullet imbalance, etc.

What rifling profile does the Bart have? How do the lands look when you’re scoped the bore?

Just a thought.

Every barrel maker makes a turd once in a while. I had one from a major manufacturer that I could not get to shoot. After about 300 rounds and doing everything I could think of I called the maker and they said to send it back. They said they found nothing wrong but replaced it anyway. Guess what? New barrel shoots little tiny groups.

This one is a 5r. I never suspected a turd would shoot something well.

This was the "best" ever with 200gr pills.

What's the length of the bullet that's giving you problems?

1.508"

Same exact bullet and velocity in a different 10 twist proof/winchester.

When you try to check the twist on the Bartlien, what do you come up with? Doesn't sound like a 10 inch twist to me. Any sign, whatsoever, of the longer bullets tipping on impact? try shooting some at fifty yards and look carefully at the holes. Generally, if shorter bullets shoot well and longer ones don't, it's twist. GD

Per JBM's site, that bullet @2700 and twisted 1:10 gives a Sg of 1.6 and change. Change the twist a 1:12 and it's 1.1 which is getting pretty herky.

Check the twist using a new brush on the cleaning rod rather than a patch and see what you come up with.

This is the barrel with the tight spot 8" from the muzzle, right?

Good shootin' -Al

I agree with the posts above, in terms of a plan of attack. Analyze the roundness of the bullet holes made by the 200s and carefully measure twist rate of the barrel.

I also had this happen once with a reputable maker. Wasted a huge amount of time in load development, it shot a few loads fairly well but everything else looked like a shotgun pattern. Spun a new barrel on and with the same stock, bedding, mounts, and scope, it shot bugholes.

But you might as well check just to make sure they didn't give you a 1:12 or something.

High Country ive got a 5R 10 twist Bart shooting 215 Bergers just fine. Like stated above if its a 10 twist call Frank at Bartlien.

I did call them, they offered to look at it. I will buy another one and spin it up as I don't have the time to play song and dance.....then refit a tube. This one patches 10".

I did call them, they offered to look at it. I will buy another one and spin it up as I don't have the time to play song and dance.....then refit a tube. This one patches 10".
If I use a brush, it shows 14, a tight patch shows 10...bizarre.

I did get shards of carbon when I tight patched it to measure....they looked like slivers on the patches. This tube hasn't ever had more than 18 rounds fired between cleanings and if it were to take more than that it's future is probably going to be chips in my lathe pan.

I'll be in Potlatch next weekend. You can swing by and give that barrel to me and I'll fight with it for a bit. GD

Hmmm gain twist?

I was thinking that too, but really it doesn't matter to me. If it's not going to shoot the 200.20x and h1000 or h4831....I want it out of my life. I have enough of the above to wear it out.