Freebore issue

[ncfyrfyter]

Hey everyone, new member here. I've read a lot of good info on here for years, but have now become a member so that I can join in on the discussions.

I have been reloading for about 7 years and have had great success developing loads for all of my rifles. I am in somewhat of a dilemma with one right now though. I have a custom built 7mm STW, that has too much freebore to allow seating the bullet anywhere near the LANs. Max SAAMI is 3.600, and in order to seat the bullet .020 (personal preference) off the LANs, the OAL is 3.762. I've tried working up loads seating to the SAAMI specs, but cannot get any really good groups and the muzzle velocity is way lower than what it should be for what I'm loading. Would seating the bullet out that far cause any issues with anything other than not being able to use the magazine?

 

[MagnumManiac]

It depends on what you feel is more important, using the mag or single loading only. Only your preference will matter, it won't effect anything either way.
If your rifle has that much freebore, then you can increase the powder charge until you get book velocity or pressure signs, whichever comes first.
Quite often near max or max loads will tighten groups up in belted mags, even with a long jump to the rifling, most of my 300's have extra long throats to achieve higher velocities in my 26" and 28" barrels, I normally load to within .010" of mag length and then try seating deeper by .005" increments until I find a good depth for that load/bullet combo.
You can of course seat to your preferred .020" off the lands and call it good, but there is almost always 2 lengths that will show an increase in accuracy, one close to the lands and one much further away, sometimes if the load is very consistent there can be quite a few lengths from the lands that work, experimentation is the key.

Cheers.
gun)

 

[willy one shot]

I kinda agree if accuracy is most important don't use clip. id also be sure to fire new brass then reload then u can neck size and bump the shoulder back if its for hunting I also agree make sure u have plenty of room to for your clip to work easy. id just use factory I took a doe at 500yards give or take a few. with federal ammo. it doesn't seem to make much of a difference in a hunting application. I love my sendaro stw it has never let me down. hope this helps

 

[ncfyrfyter]

Thanks for the info guys! I guess since I'm an extreme accuracy freak (3shots, 1 hole) kind of guy, I'll just load them .015-.020 off the LANs and not use the magazine. If it will shoot that accurately, I'll only need one shot anyway right?

 

[AZShooter]

Term is LANDS not Lans. There are plenty of rifles that shoot just fine with a jump to the rifling. Freebore does tend to lessen pressure. Perhaps you can work up safe loads with a bit more powder to get your velocity?

If you were to try Berger hybrids you will find they are very seating depth friendly. In fact my experiences all bullets tried have worked just fine with any seating depth I tried! I simply seat to fit and feed from magazine and work up powder charges.

Longest jump with a berger is .160" in a 300 WSM with excellent accuracy.



Berger recommends the following test to find your rifle's VLD sweet spot.

Load 24 rounds at the following COAL:
1. .010″ into (touching) the lands (jam) 6 rounds
2. .040″ off the lands (jump) 6 rounds
3. .080″ off the lands (jump) 6 rounds
4. .120″ off the lands (jump) 6 rounds

Berger predicts that: "One of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005."

I see no reason why this approach wouldn't work with other bullets. Why make a single shot out of a repeater?

 

[Lefty7mmstw]

I guess I'll bat on this one since I also have a custom 7stw with a good jump to the lands. I load to 3.650" and she's throated to take a pill at 3.800". Freebore is only an "issue" if you aren't tailoring your loads to a (well built) rifle properly.
First, is everything on the rifle tight and in great condition?? If not, fix your rifle.
Then, check your twist rate. Many 7stw's are built with 10" twist bores (mine is) so you can't crank a pill heavier than 160 grains or so fast enough to stabilize it.
If there isn't something amiss there, what's your load?? 7stw's are rather overbore and they are sometimes a bit of work to figure out. There is a hell of a braintrust in the stw sub forum to help you work your rifle up before you shoot her out.

I personally shoot 82.0 rl25 with a 140 nos abond in either win or rem brass at 3.650" lit with a 215. My pops subs the 140 sierra pro hunter and rl22 at 78 grains or so for his rifle. He's got a bdlss dm- brake and it's one of the most deadly pipes I've ever seen. It ranks up there with my lh a-bolt ss stalker boss 300win.

 

[ncfyrfyter]

Thanks for the input lefty! I will definitely check out the STW sub forum! I have tried RL22 in loads from 69-75 grains (in half grain increments) using 140 gr Nosler CTBT's, H1000 from 74-79 (half grain increments) same bullet, RL22 65.5-71 (halves again) using 150gr Nosler CTBT's and H1000 68.5-74 (half increments) same bullet. I use Winchester brass and Federal 215 primers. I've gotten a couple 1" groups with both bullet weights, using RL22 with the 140's and H1000 with the 150's. I believe everything to be correct with the rifle and I believe it is capable of sub MOA groups with the right powder/bullet combination. Just got some RL 25 and some Viht N165. I have some new optimism that one of these will do the trick. Gonna go check out the sub forum and pick my fellow STW shooters brains for some good recipe ideas!