Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Hunting > The Basics, Starting Out


Reply

bolt lug contact

 
LinkBack Thread Tools Display Modes
  #8  
Old 12-10-2005, 10:47 AM
Official LRH Sponsor
 
Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,822
Re: bolt lug contact

Harv,

First off, what is that bolt out of? Looks like a Sako bolt as there is a sako extractor to the left of the lug in the first pic, or at least looks like one.

Could be a Rem 700 with a Sako fitted but the guide groove looks to large in the right lug. Also, the groove behind the lugs on the bolt body is not right for a Rem 700 unless it has been altered.

Anyway, the lug contact appears to be relatively even. I would say in the 70-75% range. On the leading edge of the lugs, Right side in the pics, there is a cam machined which is why that area does not contact the receiver when the bolt is locked, this is desirable and should not be machined out.

On the left side of each lug there is that triangle pattern on the bottom of the lug surface.

Without knowing exactly what receiver this is I would not want to say either way if this area should be corrected but I will say it is desireable in most cases to have this area fully contacting.

As far as the gauling is concerned. ITs hard to tell in the pics if it is actually gauling or old machine marks that are present and visible through the polished areas of the lug.

In the top pic, it appears that this is just machining marks as you can see the line on th ebaring surface near the top of the lug. I say this because the groove is consistant in width from start to finish. Generally gualing will increase in size or width as it progresses as more metal is balled up if you will.

In the bottom pic, there is one area on the right side of the contact area about 1/3 up from the start of the bolt body that appears to be some gauling. Just to the left of this is what appears to be a brass smear. This tells me that brass chips have gotten between the bolt lug and receiver surface and may be the reason for the gualing.

Keep thise bolt lug recesses clean and free of dirt and brass chips and use a high quality moly based lug grease to lube these surfaces when needed. I generally lube every 25 rounds.

Most importantly, how is the rifle shooting right now?

Kirby Allen(50)
__________________
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
Reply With Quote
  #9  
Old 12-10-2005, 11:39 PM
 
Posts: n/a
Re: bolt lug contact

Thanks for all the replys. The rifle is a Tikka 270. I loaded 130g wildcats this year and all loads shot under 1" at 100y. Best was just under 1/2". The rifle is basicly stock. I sanded the forend out so I have at least 1/8" clearance between barrel and stock. Also added about 3lb led to the syntec stock. Kirby, what's your thought on neck sizing only for this rifle. I started doing this in hopes of a little better accuracy but was wondering if I will run into any problems after a few reloads? Thanks.
Reply With Quote
  #10  
Old 12-11-2005, 10:57 AM
Official LRH Sponsor
 
Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,822
Re: bolt lug contact

Harv,

Really depends on how heavy you load the 270 Win. Neck sizing only works great for accuracy but if you load to top levels you will quickly need to bump the shoulder to maintain easy chambering. You can let that be your judge on when to bump the shoulder.

Do some testing and see if the rifle shoots better with neck sized only or partial Full Length sized cases. Despite conventional wisdom, many factory rifles shoot more consistantly with partially full length sized cases because they are not baring evenly on the bolt lugs.

If the bolt lug baring surface is not square, generally a preload on the bolt will cause unexplained fliers at times. This Bolt preload can be caused by only neck sizing so test her out and see how your rifle responds. Your lugs look relatively even but its impossible to tell if they are square without putting a mic to them.

From what I have seen with the Tikka rifles, the most limiting factor to accuracy is their synthetic stocks, very flexible in the receiver area.

If you get a load in the 1/2" range I would say you have done very well and to stick with that.

Again, test the neck sizing only against the partially FL sized cases and see if there is any accuracy difference. If you decide to neck size only, it is imparative to keep those lug surfaces lubed with quality lube as there will be more force applied to them when the bolt is closed. Keep them clean as well!!

Good Shooting!!

Kirby Allen(50)
__________________
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
Reply With Quote
  #11  
Old 12-13-2005, 09:50 AM
 
Posts: n/a
Re: bolt lug contact

Thanks much Kirby. I will have to rethink this neck sizing only thing. I lube the lugs every time I clean the bore (25-50rounds). Been having good luck with FL sizing so mabe I'll go back to that. Just trying to get the best accuracy from this factory rifle without spending too much. Saving my pennies for a custom AM ..... some day.
Reply With Quote
  #12  
Old 12-13-2005, 10:26 AM
Official LRH Sponsor
 
Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,822
Re: bolt lug contact

Harv,

Adjust your FL die a little at a time while checking how the sized case chambers in your rifle. Just when you get the case to chamber easily stop there. you will have about 0.001" clearance which will offer great accuracy but still keep chambering easy.

I generally turn my FL die down about 1/16 a rotation at a time when setting it up to size cases. When they start getting close to chambering ease, I cut that in half again and work up to that point slowly.

Good Shooting!!

Kirby Allen(50)
__________________
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
Reply With Quote
  #13  
Old 12-13-2005, 01:19 PM
 
Posts: n/a
Re: bolt lug contact

I have only gone one round of neck sizing and no problems chambering them. Should I just keep neck sizing until I get resistence when chambering and than bump the shoulder a bit?
Reply With Quote
  #14  
Old 12-13-2005, 03:45 PM
Official LRH Sponsor
 
Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,822
Re: bolt lug contact

Harv,

Yes, you will have to play with it a bit and see how many firings you can get before you need to bump the shoulder. If your not runnng really hot loads this will generally be every 3 firings or so.

Kirby Allen(50)
__________________
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: bolt lug contact
Thread Thread Starter Forum Replies Last Post
who to contact???? HANDLER Long Range Scopes and Other Optics 6 07-16-2010 11:29 AM
Maybe we should all contact this guy Tyler Kemp Reloading 9 12-15-2007 03:19 PM
Bolt Lug Contact & how it effects groups gonehuntingagain Rifles, Bullets, Barrels & Ballistics 5 04-18-2006 04:16 PM
Brown Dog contact me Pete Lincoln General Discussion 0 02-02-2005 02:23 AM
Ken Farrell contact # Long Range Hunting & Shooting 4 09-15-2003 07:14 AM


All times are GMT -5. The time now is 07:41 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC