Fat bolt rifles - I like 'em

[mississippishooter]

I started a thread asking for suggestions in a budget bolt 7mm-08 that I wanted for reasons I can't clearly express and that I've attempted to explain elsewhere. So I'm moving on...

One of my clear preferences, though I didn't know it when I first met a Ruger American in approximately 2008, is for a three-lug bolt in a bolt-action rifle over a two-lug system. What I knew then (or perhaps, what I said I liked about my buddy Matt's rifle) was that the bolt handle didn't have to nearly hit the scope for the action to be opened. My cheap-o, but accurate Mossberg 100 ATR functioned fine, but lacked that refinement.

Later, when trying to get the Interwebs to tell me what kind of bolt action I wanted, I learned that the locking recoil lugs on the bolt that slide into place and lock when lowering the bolt handle come, mostly anyway, in two flavors: the two- and three-lug designs.

Two lugs? My Mossy, of course, my dad's old Remington 700, any of the accurate and highly touted offerings from Savage, Weaver and others. MOST of the classics have the two-lug design.

The Thompson Center offerings (Compass, Venture and Dimension) and the Ruger series actions have "fat" bolts. I found I liked this better. Substantially better. It's mostly a clearance issue for me, but the short of it is that a "fat" bolt will open with a 60 degree lift while a traditional two-lug bolt requires a 90 degree lift with the bolt handle riding along close the edge of the scope for some of us.

I was pondering this tonight, googled the issue and found this excellent article. I had read about the differences, but had never heard the term "fat bolt." I grew up hunting, but I've been out of the rifle market for several years, so it's probably a testament to my ignorance.

Read it if you can. Good stuff.

 

[horsemen61]

I like the old school 2 lug but I don’t hold a grudge against a 3 lug bolt

 

[mississippishooter]

I tend to like the classics myself which is why this feels like such a big deal to me. It's out of character.

 

[MCMXI]

I've not heard the term "fat bolt" before but do use the common term "full diameter bolt". I don't agree with the authors simplistic notion that full diameter bolt rifles are cheaper to manufacture, or that they're more accurate than two lug bolts. Rifle costs are far more complex than the type of action or bolt used. Also, there are way too many two-lug bolt guns out there that exhibit top tier accuracy/precision to make any compelling statement about the superior performance of full diameter bolts. I have "tactical" rifles with full diameter bolts and multi-lug arrangements as well as hunting rifles with just two locking lugs. I will agree that a 60 degree bolt throw is a plus for the reasons stated, assuming that the primary extraction works well and bolt lift is not adversely affected.

 

[LoonWulf]

I mostly have skinny bolties, but some of my favorite budget rifles are the Americans, and I'm playing with Mauser M-18.
I guess my abolts kinda a fatty, but that's mostly the shroud.

 

[DocRock]

One of my all time favorite rifles and one that I shoot monthly in competition is a skinny one lug Krag - Jorgensen. That bolt moves like greased lightening.

But, I don't hunt with it and I only shoot cast bullets at 1700 fps, so, I'm with you. For a modern hunting bolt gun chambered in a modern, high pressure cartridge, give me the plumper. Three lug or, better yet, the Weatherby Mark V nine lug.

 

[someguy2800]

Some 2 lug bolt actions also have a 60 degree bolt lift. Tikka T3's for instance. Browning X-bolt and A-bolts also have three lug bolts with a 60 degree throw, but do not have a full diameter bolt.

I guess if I had to pick I prefer a narrow bolt for no particular reason than aesthetics. I do have a preference for a 60 degree bolt lift, but its not that big of a deal. Neither of these things would be enough to make me like or dislike a certain rifle.

 

[Gtscotty]

Some 2 lug bolt actions also have a 60 degree bolt lift. Tikka T3's for instance. Browning X-bolt and A-bolts also have three lug bolts with a 60 degree throw, but do not have a full diameter bolt.

I guess if I had to pick I prefer a narrow bolt for no particular reason than aesthetics. I do have a preference for a 60 degree bolt lift, but its not that big of a deal. Neither of these things would be enough to make me like or dislike a certain rifle.

I believe Tikkas have a 70 degree bolt lift and sako A7s and 85s have a 60 degree. The Tikka throw angle is attenuated enough to give you pretty much the same clearance benefits the three lug actions are known for though. I'd say I prefer the shorter bolt throw in the Browning, Ruger and Tikkas I've had, but I still get along fine with the 90 deg throw in rifles like M70s and Kimbers.

I've had rifles with full diameter bolts and normal reduced diameter bolts, other than the fact that full diameter bolts must add a little bit of weight, I dont really have a preference.

 

[Skylerbone]

I’m marred by the most common drawback to economy model short lift bolts which is their feel. Drawing one back as it wallows around loosely is far from a satisfying experience when compared to a Winchester, CZ, or Tikka. That’s not to say all of each is like the others and I own examples in both 2 and 3-lug.

 

[jmr40]

I've not heard the term "fat bolt", but I do believe a stiffer bolt is one contributing factor to better accuracy.

 

[mississippishooter]

As accuracy goes, I've not seen anyone make a reasonable argument that 3 beats 2 (or if I have, it didn't stick). The accuracy of Savage, Remington, the Winchester Model 70, etc., is legendary. All are based on the 2 lug Mauser design. For me, it's the shorter lift and the extra space between the bolt handle and scope. I'm not precision shooting. Just looking for a decent hunting rifle that will make good 100 yard shots with a RARE 150-200 yarder tossed in if I'm so inclined. If I can show off on paper, great. If not... Well, then not.

 

[Varminterror]

“As accuracy goes,” I would present evidence that three lug actions aren’t very common in benchrest or precision rifle competition. Guys who spend enough time, money, and ammo to see the difference between the two haven’t found an accuracy advantage, so I’m prone to suggest one doesn’t exist. If there were an advantage, every rifle on a competition firing line would be a 3 lug. Alternatively, the overwhelming majority of competition rifles are 2 lug actions.

There were several points of silliness in the article, but overall, it wasn’t a bad piece. One thing I found to be funny - the author credits himself with coining the phrase “fat bolt” 50 years ago; it didn’t catch on then, and I doubt it will now. He also used the unique term “tri-lug.” “Full diameter” and “three lug.” I found it silly to extol the virtues of injection molded stocks, especially claiming every injection molded stock is exactly the same - when any gunsmith or anyone in injection molded polymer industries would tell you these stocks have as much opportunity to warp during cure and flex as any wood stock has ever had. There’s a proven fallacy in “even contact,” as well as fallacy in “more support” in a 3 lug action - anyone with calipers can line out that lie for themselves.

Personally, I was intrigued by the OP’s fervent disdain for 90degree throw bolts in his other thread, specifically how much trouble he seems to have with proximity to the scope. I have to say, in owning and servicing hundreds of rifles - including a majority which were NOT set up for my eye relief or stock fit - I have never slammed my hand between a bolt handle and a scope. Just doesn’t happen. I’ve had handles hit optics, but never created a pinch point for myself. Not sure how that fails for some folks. 60 degree bolts do offer greater clearance, and there’s nothing bad about the short throw, I just can’t figure out how guys are holding their bolt knobs such they smash their hands or fingers against scopes.

One extreme DISADVANTAGE I have found in “fat bolt,” full diameter bolt rifles is the opportunity to crash the magazine, and to crush rounds on a short stroke. The larger diameter bolt body won’t ride as well between mag lips, and it offers double the opportunity to crash the magazine (the forward bolt and lug face, and the intermediate step from the bolt head to the body). Short stroking a 2 lug design can cause a mis-feed, no doubt, but it can also simply fail to pick up, and glide smoothly over the top of the missed round. With “fat bolts,” I’ve noticed the bolt body will almost always pick up the rim of the case, indexing the round forward to be crushed between the bolt face and the feed ramp. It happens reliably, and far more often than the same damaging failure in a traditional 2 lug design with a narrow bolt body.

As others have mentioned, the larger diameter bolts also have greater opportunity to bind. The larger diameter, differentially, acts more like a flat surface with greater adhesion, and greater opportunity to “catch,” than a smaller diameter bore.

Both types have advantages and disadvantages - and further more types exist than just 2 lug skinny bolts and 3 lug fat bolts.

 

[taliv]

i have pinched my hands many times between handle and scope, but i'm left handed and used S&B a lot.

i have some 60* and thought they were sliced bread when i first discovered them, but quickly went back to 90* because disadvantages outweighed the advantages.

i will say, the Accuracy International would be the exception and I'd use one without hesitation

 

[Legionnaire]

I voted either one, even though most of mine are two-lugs. Number of lugs has never been a significant deciding point for me.

 

[Varminterror]

i have pinched my hands many times between handle and scope, but i'm left handed and used S&B a lot.

Where on your hand? I hear guys say it, but I haven’t witnessed it, and it never comes up in my bolt throw, so I’ve been at a loss on this one for years. Only thing I come close to is crashing my thumb on the drawstroke on the objective bell - and the bolt handle has to be close enough for it to hit on it’s own path too - or very nearly so. My hand is never on the optic side. So this particular shooter affliction has been a mystery to me for a long time.

 

[mississippishooter]

“As accuracy goes,” I would present evidence that three lug actions aren’t very common in benchrest or precision rifle competition. Guys who spend enough time, money, and ammo to see the difference between the two haven’t found an accuracy advantage, so I’m prone to suggest one doesn’t exist. If there were an advantage, every rifle on a competition firing line would be a 3 lug. Alternatively, the overwhelming majority of competition rifles are 2 lug actions.

There were several points of silliness in the article, but overall, it wasn’t a bad piece. One thing I found to be funny - the author credits himself with coining the phrase “fat bolt” 50 years ago; it didn’t catch on then, and I doubt it will now. He also used the unique term “tri-lug.” “Full diameter” and “three lug.” I found it silly to extol the virtues of injection molded stocks, especially claiming every injection molded stock is exactly the same - when any gunsmith or anyone in injection molded polymer industries would tell you these stocks have as much opportunity to warp during cure and flex as any wood stock has ever had. There’s a proven fallacy in “even contact,” as well as fallacy in “more support” in a 3 lug action - anyone with calipers can line out that lie for themselves.

Personally, I was intrigued by the OP’s fervent disdain for 90degree throw bolts in his other thread, specifically how much trouble he seems to have with proximity to the scope. I have to say, in owning and servicing hundreds of rifles - including a majority which were NOT set up for my eye relief or stock fit - I have never slammed my hand between a bolt handle and a scope. Just doesn’t happen. I’ve had handles hit optics, but never created a pinch point for myself. Not sure how that fails for some folks. 60 degree bolts do offer greater clearance, and there’s nothing bad about the short throw, I just can’t figure out how guys are holding their bolt knobs such they smash their hands or fingers against scopes.

One extreme DISADVANTAGE I have found in “fat bolt,” full diameter bolt rifles is the opportunity to crash the magazine, and to crush rounds on a short stroke. The larger diameter bolt body won’t ride as well between mag lips, and it offers double the opportunity to crash the magazine (the forward bolt and lug face, and the intermediate step from the bolt head to the body). Short stroking a 2 lug design can cause a mis-feed, no doubt, but it can also simply fail to pick up, and glide smoothly over the top of the missed round. With “fat bolts,” I’ve noticed the bolt body will almost always pick up the rim of the case, indexing the round forward to be crushed between the bolt face and the feed ramp. It happens reliably, and far more often than the same damaging failure in a traditional 2 lug design with a narrow bolt body.

As others have mentioned, the larger diameter bolts also have greater opportunity to bind. The larger diameter, differentially, acts more like a flat surface with greater adhesion, and greater opportunity to “catch,” than a smaller diameter bore.

Both types have advantages and disadvantages - and further more types exist than just 2 lug skinny bolts and 3 lug fat bolts.

No disdain here (fervent, partial, or marginal)! I prefer 3 lugs. My wife's a brunette and I chose her. I can still appreciate and respect blondes and redheads.

RE: Smashed fingers... My issues have come from shooting at game when I've handled the bolt differently than I do at the range. Some of that's because of shooting from odd positions, wearing gloves in cold weather or just the moment of excitement that comes from making the shot. Of course more practice and rounds downrange might fix that, so I gladly accept the notion there's plenty of shooter error involved (There it is: a confession that ignorance and lack of training plays a role. In my defense, I am working on it.).

I was also saying that accuracy isn't a factor in my argument (or any other I know of), as there is no accuracy advantage in the 3 lug design I've heard, read or seen anywhere. I pointed to the incredible reputation of accuracy of several 2 lug rifles, so I guess you were agreeing with me on that point. Bolt actions' general reputation for accuracy comes from 2-lug rifles modeled on the Mauser.

My preference for the shorter lift boils down to "why not." I find a shorter lift and more scope clearance helpful. And if I can have that at no significant disadvantage for my purposes, why not? I just thought it was an interesting (if not a fun) question. If I came off negative, my apologies. I find this (among many others in shooting) an interesting subject.

 

[taliv]

take a look at the ocular housing and illumination control knob on a schmidt und bender pm2 5-25
imagine a left handed bolt
if you're holding the bolt with your finger on the muzzle side and thumb on the butt side, doing the old "grip it and rip it", when you jerk the bolt back, you will crush your thumb on the nail.
on my rifles, there's typically a quarter inch clearance between the bolt itself and that knob on the scope at the fully open position, which is just not enough room for my thumb. so my method of running the bolt was simply to use the sort of karate knife hand and my index finger would push the bolt up, then 1-finger pull it back and 1 finger push it forward without having an actual 'grip' on the bolt. this eliminated getting my fingers pinched. but a couple times a year i'd forget and grip it.

 

[Varminterror]

@taliv - a lefty banging into that intensity knob makes a lot of sense. Smashing the thumb on the draw stroke is the only feasible means I have ever been able to imagine, but guys seem to always say, “smash my hand,” so I assumed I was picturing the wrong fault.

My habit is running my bolt with my palm vertical, such my thumb stays vertical, meaning it hides behind the bolt knob, with the tip folded over the top. Much like casting a fishing rod from overhead (not flipping to the side). If my bolt knob clears, my thumb clears. Even on my rifles which have hit the ocular housing on the handle shank, my thumb clears. My son flares his elbow and wrist when he runs the bolt, but I work to coach him out of it - hand/wrist strength is his issue, being 6yrs old, but I’m trying to avoid establishing a bad habit.

So maybe I believe words too much. I read, “I smash my hand between the bolt knob and scope,” and I expect they mean their hand. I can get on board with smashing your thumb against a fat ocular housing or other protrusion. Can’t figure out how to smash my hand though. It’s just natural for me to run my palm vertical, so it’s never happened to me. I don’t remember being coached to cycle my bolt that way, but maybe I was taught such?

I had to run down to my gun room today and play with a few rifles. Thinking about a lefty bolt, zoom levers would be a big problem! Even a 60 degree bolt wouldn’t clear. Bolt handles and knobs won’t clear, let alone thumbs wrapped around them. The only left bolts I have are Savage Strikers, and I don’t have zoom levers on those. I guess, chalk that up to #leftyprobs

Sorry for the derailment - this has been one of those “gun things” I simply haven’t been able to figure out. If someone is smashing their HAND, I want to see a video. Thumbs, I can buy. Hands? No way. So this has been a topic which has itched in the back of my mind for many, many years.

 

[IdaD]

My Remington 700 rifles operate fine and I'm totally satisfied with them, although I prefer the 9 lug action on my Mark V.

 

[taliv]

I had to run down to my gun room today and play with a few rifles. Thinking about a lefty bolt, zoom levers would be a big problem! Even a 60 degree bolt wouldn’t clear. Bolt handles and knobs won’t clear, let alone thumbs wrapped around them. The only left bolts I have are Savage Strikers, and I don’t have zoom levers on those. I guess, chalk that up to #leftyprobs

never had a problem with throw levers cause i just put them on the other side lol
i do have a bit of a problem with the NF because their entire ocular housing rotates when changing zoom and that moves the flip cap into my way.

 

[mississippishooter]

@taliv - a lefty banging into that intensity knob makes a lot of sense. Smashing the thumb on the draw stroke is the only feasible means I have ever been able to imagine, but guys seem to always say, “smash my hand,” so I assumed I was picturing the wrong fault.

My habit is running my bolt with my palm vertical, such my thumb stays vertical, meaning it hides behind the bolt knob, with the tip folded over the top. Much like casting a fishing rod from overhead (not flipping to the side). If my bolt knob clears, my thumb clears. Even on my rifles which have hit the ocular housing on the handle shank, my thumb clears. My son flares his elbow and wrist when he runs the bolt, but I work to coach him out of it - hand/wrist strength is his issue, being 6yrs old, but I’m trying to avoid establishing a bad habit.

So maybe I believe words too much. I read, “I smash my hand between the bolt knob and scope,” and I expect they mean their hand. I can get on board with smashing your thumb against a fat ocular housing or other protrusion. Can’t figure out how to smash my hand though. It’s just natural for me to run my palm vertical, so it’s never happened to me. I don’t remember being coached to cycle my bolt that way, but maybe I was taught such?

I had to run down to my gun room today and play with a few rifles. Thinking about a lefty bolt, zoom levers would be a big problem! Even a 60 degree bolt wouldn’t clear. Bolt handles and knobs won’t clear, let alone thumbs wrapped around them. The only left bolts I have are Savage Strikers, and I don’t have zoom levers on those. I guess, chalk that up to #leftyprobs

Sorry for the derailment - this has been one of those “gun things” I simply haven’t been able to figure out. If someone is smashing their HAND, I want to see a video. Thumbs, I can buy. Hands? No way. So this has been a topic which has itched in the back of my mind for many, many years.

To your point, it seems my thumb is more of the problem than my hand. The knob on my scope on my Mossberg protrudes a bit but eye relief is right, so I don't want to mess with it. I tend to drape my thumb over the bolt knob when grabbing it, mostly with my index and middle fingers. At the top of the arc, the lower part of my thumb has gotten pushed between the bolt handle and the scope knob. And it racks it pretty good when that happens. It's really only when I'm on target on game.

 

[Gtscotty]

RE: Smashed fingers... My issues have come from shooting at game when I've handled the bolt differently than I do at the range. Some of that's because of shooting from odd positions, wearing gloves in cold weather or just the moment of excitement that comes from making the shot.

My fingers don't get smashed, more like cramped enough to throw off my stroke sometimes, but this is where I've run into it as well, hunting in cold weather with gloves on and shooting from odd positions. The bolt handle on my Kimber isn't very long and there's not much room between it and the low mounted ocular bell for fingers and gloves. Same with the M70s I've owned, not a huge deal, but for a hunting rifle, I do prefer a shorter bolt rotation over a standard 90 degree.

 

[MCMXI]

One extreme DISADVANTAGE I have found in “fat bolt,” full diameter bolt rifles is the opportunity to crash the magazine, and to crush rounds on a short stroke. The larger diameter bolt body won’t ride as well between mag lips, and it offers double the opportunity to crash the magazine (the forward bolt and lug face, and the intermediate step from the bolt head to the body). Short stroking a 2 lug design can cause a mis-feed, no doubt, but it can also simply fail to pick up, and glide smoothly over the top of the missed round. With “fat bolts,” I’ve noticed the bolt body will almost always pick up the rim of the case, indexing the round forward to be crushed between the bolt face and the feed ramp. It happens reliably, and far more often than the same damaging failure in a traditional 2 lug design with a narrow bolt body.

As others have mentioned, the larger diameter bolts also have greater opportunity to bind. The larger diameter, differentially, acts more like a flat surface with greater adhesion, and greater opportunity to “catch,” than a smaller diameter bore.

I've never experienced either issue with my Accuracy International rifles and thousands of rounds fired. It all comes down to execution and if it's done right it works right. It amazes me how many rifles don't run well even when pushed moderately hard. I took a two-day "sniper" course a few years ago and it was ridiculous how many shooters had issues as the time allowed for each drill was reduced. A bunch of shooters left that course realizing that they need a better rifle.

 

[Steve S.]

Old school here, all two locking lugs and no smashed fingers, all are substantially accurate. Three lugs are just Jim Dandy, stop smashing your fingers, buy what you like, do not shoot loads hot enough to shear any count of lugs, lots of practice negates lug count.

 

[Varminterror]

It amazes me how many rifles don't run well even when pushed moderately hard.

@taliv has said it exceptionally well here many times - so many guys will choke a rifle to death, over and over, on the clock, then say after the match, the rifle never fails.

A shooter on my squad last weekend was baffled at a couple “kinked” rounds he crushed on the clock. Odd positions elicited short strokes, RO’ing for our squad, another shooter and I watched it, clear as day. Another shooter asked what could have caused it, and he started digging in the bottom of the barrel for excuses that his feed rails were wrong and his mags needed tweaking to run with his coal... the other “squad mom” pointed out to the new shooter, “nah, that’s a short stroke. He didn’t draw the bolt all the way back when his hand was wedged beside that tire, and the boltface missed the round - unfortunately, the body picked up the rim and fed it far enough to get crushed.” Deflated, the guilty shooter started to pack and move on, so I lightened the squad by calling myself out for short stroking and choking my rifle too, “yeah, remember on 3 when I dropped my mag? That was the same deal.”

If you run it right, they run right. But that full diameter bolt body is happy to pick up and crush cases if you don’t.