I bought a Rem 700 heavy barrel in 308 used. Tried many different loads but can't get it to shoot good groups. Checked the headspace and it measures 1.636. Seems to be right in between nogo(1.634) and field(1.638). Is there something I can do to the bolt to tighten things up? Tried a bolt from another 700 and it measured 1.634 (nogo). Also how do you measure barrel length? I know the front is measured from where the rifling ends and not the end of the muzzle brake but what about the action end? The reason I am asking is this barrel is close to the min length and I am trying to avoid buying a new barrel. Any help would be greatly appreciated. Thanks.
Bolt action headspace
- Thread starter hooligan
- Start date
Do you handload? If so,you can adjust the sizing of the brass so that the cases fit the chamber perfectly. Or just necksize the cases fired in the rifle. Doing this can help accuracy. No factory Rem 700 comes with a short barrel with a brake. What do you know about the barrel, its quality, history, etc. The CFC definition of barrel length is from the boltface to the muzzle face, not including a detachable brake.
- Location
- Somewhere on the Hudson Bay Coast
Measure the barrel length from the muzzle to the face of the closed bolt. There is no minimum barrel length with a bolt gun...many believe that short barrels out shoot long barrels due to increased stiffness.
If your head space was an issue you would see indicators on your fired brass. You might want to play around with the seating depth of your bullets, but it has been my experience that an accurate rifle will shoot any reasonable load fairly well. Perhaps you have bedding issues with the rifle, or there could be some sort of problem with the crown of the barrel. Try shooting without the brake - that can change barrel harmonics, or if improperly installed the bullet could touch the brake as it passes. Is there copper fouling on the brake?
If your head space was an issue you would see indicators on your fired brass. You might want to play around with the seating depth of your bullets, but it has been my experience that an accurate rifle will shoot any reasonable load fairly well. Perhaps you have bedding issues with the rifle, or there could be some sort of problem with the crown of the barrel. Try shooting without the brake - that can change barrel harmonics, or if improperly installed the bullet could touch the brake as it passes. Is there copper fouling on the brake?
J
JoeP's old business account
Guest
What size are your groups and at what distance and under what conditions?
Type of ammo you are using?
Number of rounds fired by the previous owner/owners?
The more info you can give the better are the odds of determining what the problem is. Amoung other things, you might want to look at the crown. This will influence accuracy as well. Uniform and symetrical machining is what you are looking for. No burrs/nicks or damage to the leading edges of the bore.
Joe
Type of ammo you are using?
Number of rounds fired by the previous owner/owners?
The more info you can give the better are the odds of determining what the problem is. Amoung other things, you might want to look at the crown. This will influence accuracy as well. Uniform and symetrical machining is what you are looking for. No burrs/nicks or damage to the leading edges of the bore.
Joe
The rifle is a Rem 700 VSSF 308, barrel cut down to 18.75 with I believe a Dlask muzzle brake installed. Action has been glass bedded including about 1" of the barrel. The rest of the barrel is free floating.
I have tried Remington core-loct 150 and 180gr, Federal GMM 175gr, and various handloads with 175 and 168gr Sierra mk. Recently bought Federal match primers so will be trying those. Have been using regular CCI primers. Do primers make that much of a difference? I guess I will have to go out and buy some Federal GMM 168gr to try as the previous owner mentioned that it likes 168 gr best. Can you neck size with a fl sizing die or do I have to buy a new die? Read somewhere that you can, just can't remember how.
Brake looks clean, crown looks good to me. Previous owner said he put about 500 rnds through it and I put about 200. Best I can do to date is about 4-5" at 200m. My other VSSF in 308 will do 1" at 200m with me behind the trigger so I don't think the problem is me. The range I shoot at is surrounded in trees so I don't think wind is much of a factor at 200m. Am using Leupold 1 piece base, unknown rings (look solid) and Bausch & Lomb elite 4000 6-24 scope.
Is the mentioned headspace ok? If someone tells me that tightening up the headspace will definitely improve things I will just do that first before playing with it more.
When I started out handloading I read from many people that is is fun. I agree but can also be very frustrating. It is really annoying me that Port surplus 7.62x51 shoots about as well as my "match" loads. Maybe it is my loads that are inaccurate?
Thanks for the help guys. I really appreciate it.
I have tried Remington core-loct 150 and 180gr, Federal GMM 175gr, and various handloads with 175 and 168gr Sierra mk. Recently bought Federal match primers so will be trying those. Have been using regular CCI primers. Do primers make that much of a difference? I guess I will have to go out and buy some Federal GMM 168gr to try as the previous owner mentioned that it likes 168 gr best. Can you neck size with a fl sizing die or do I have to buy a new die? Read somewhere that you can, just can't remember how.
Brake looks clean, crown looks good to me. Previous owner said he put about 500 rnds through it and I put about 200. Best I can do to date is about 4-5" at 200m. My other VSSF in 308 will do 1" at 200m with me behind the trigger so I don't think the problem is me. The range I shoot at is surrounded in trees so I don't think wind is much of a factor at 200m. Am using Leupold 1 piece base, unknown rings (look solid) and Bausch & Lomb elite 4000 6-24 scope.
Is the mentioned headspace ok? If someone tells me that tightening up the headspace will definitely improve things I will just do that first before playing with it more.
When I started out handloading I read from many people that is is fun. I agree but can also be very frustrating. It is really annoying me that Port surplus 7.62x51 shoots about as well as my "match" loads. Maybe it is my loads that are inaccurate?
Thanks for the help guys. I really appreciate it.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Headspace will not affect accuracy. Just collet or bushing neck size and that eliminates any issues there. understand that factory barrels are not all the same and you can get a real dog. Maybe it needs to be cleaned, maybe it needs to be dirtier. The list to diagnose this is long.
Start with the basics. Make concentric ammo that fits the chamber and work up your loads with good components. yes, primers matter especially if ranges get further.
I would also look at the rifle itself. Is the bedding done properly? Is that scope mount tight? Looking tight is not the same as being tight. Is the throat worn out, some Rem chambers have stupidly long throats which get worse with use?
I would work up my loads with known accurate components. However, if GM ammo shoots like surplus, I would look at the rifle before wasting too much time at the range.
Jerry
Start with the basics. Make concentric ammo that fits the chamber and work up your loads with good components. yes, primers matter especially if ranges get further.
I would also look at the rifle itself. Is the bedding done properly? Is that scope mount tight? Looking tight is not the same as being tight. Is the throat worn out, some Rem chambers have stupidly long throats which get worse with use?
I would work up my loads with known accurate components. However, if GM ammo shoots like surplus, I would look at the rifle before wasting too much time at the range.
Jerry
- Location
- Somewhere on the Hudson Bay Coast
I would give the rifle a very good cleaning and work the bore with either sweets or wipeout to ensure there is no fouling. Inspect the locking lugs to ensure even lockup - although this can actually be quite poor and not effect a rifle's grouping. Ensure that all the screws on the scope mounts are tight and also the screws on your bases. Tighten up your action screws and try to detect if there is any binding or twisting of the barrel or action as it pulls into the stock.
If all the above looks good change scopes and see what happens. I still believe that if this rifle can shoot one load well, it should be able to do well with any reasonable load. Having said that however, it may be prudent to stick with bullets of around 168 grs if the former owner claimed the rifle would shoot them.
If all the above looks good change scopes and see what happens. I still believe that if this rifle can shoot one load well, it should be able to do well with any reasonable load. Having said that however, it may be prudent to stick with bullets of around 168 grs if the former owner claimed the rifle would shoot them.
Bedding looks solid to me, no noticable binding or twisting when tightening action. Action screws tightened to 65 in/lb. Scope base and rings are as tight as i would like to go given the material. Not much bolt wear on the rear of the lugs but seem to be even. The bolt actually has some play back and forth. With the bolt locked and the trigger pulled the bolt moves forward and back about 10 thou. Is this ok? When I try my other bolt in this rifle there is no play.
Bore has been shot clean and dirty. My other rifle shoots GMM like crap until I get to 175gr then turns into a completely different beast. As mentioned before 1/2 moa at 200. Thanks again.
Bore has been shot clean and dirty. My other rifle shoots GMM like crap until I get to 175gr then turns into a completely different beast. As mentioned before 1/2 moa at 200. Thanks again.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
When a bolt is closed and cocked, there should be no movement at all. Having play once the hammer has fallen can indicate generous headspace. That alone is not a big deal as the fireformed case will fill and push the bolt against the receiver for a tight lockup.
Try measuring the fired cases for runout. Also, check the throat length. I am leaning towards the throat being too long so that the bullet has a jump before engaging the lands. Time to set back or replace the barrel.
A rifle of this quality should have no issue shooting crappy 1.5MOA groups with any decent ammo. Sub MOA with something it likes. Shooting 4 to 5" groups at 100yds just tells me something is seriously wrong.
Jerry
Try measuring the fired cases for runout. Also, check the throat length. I am leaning towards the throat being too long so that the bullet has a jump before engaging the lands. Time to set back or replace the barrel.
A rifle of this quality should have no issue shooting crappy 1.5MOA groups with any decent ammo. Sub MOA with something it likes. Shooting 4 to 5" groups at 100yds just tells me something is seriously wrong.
Jerry
J
JoeP's old business account
Guest
Hooligan.
I don't think we need to focus on the headspace as being your problem. The intent of the range is for safety and not for accuracy. All rifles using factory ammunition will have clearance. As a reloader you can control the clearances and since this is where you are at, you can easily do this.
If you shoot mild loads and reload infrequently, the case shoulder may never press hard into the chamber shoulder so you will always have clearance. As you increase pressures and continue to use the brass, clearances are reduced. Eventually you will hit a point where the shoulder may bear hard into the shoulder which usually makes chambering difficult. BR shooters avoid this situation since it generally causes flyers. Normally they size or bump the shoulder so the bolt will just smoothly close on the loaded round and not disturb the gun in the bags. They may bump the shoulder, they may bump the shoulder and case head (as with a Harrell die) or they may bump the shoulder and size the body (in a custom die) to achieve this goal. They make sure all the cases chamber with the same force. Size too much and you will shorten brass life due to overworking.
BR shooters shoot for minimal or zero headspace while using a min. spec. reamer. This is easiest on brass and probably enhances safety. They generally go one step further and they go for fitted necks where the neck of the casing needs to be turned in order for the casing to fit into the chamber... a whole different story.
Factory chambers are intended to fall into a industry range. To keep costs down a maximum sized chambering reamer is used. As it (reamer) wears the tool would be reground to restore cutting edges and service life to the tool. Over time, the regrind operation will cause the reamer to hit a minimum specification - smallest reamer size. Chambers cut with this reamer are the easiest on brass and offer the tightest fit as per industry standards. Once the reamer is past this min spec it is considered scrap. Most shooters are tickled pink when they have a small chamber. The hole point is to keep the casing as aligned with the bore as possible and a oversize or max spec. chamber increases the misalignment. Reloading can help reduce the affect pending how much of the case you resize. Custom rifle builders often stick with min spec reamers despite the added tooling cost.
I would look else where for your problem. I.E. barrel, bedding, mounts, scope. If you have a spare scope, that is sometimes a quick and easy check!
Joe
I don't think we need to focus on the headspace as being your problem. The intent of the range is for safety and not for accuracy. All rifles using factory ammunition will have clearance. As a reloader you can control the clearances and since this is where you are at, you can easily do this.
If you shoot mild loads and reload infrequently, the case shoulder may never press hard into the chamber shoulder so you will always have clearance. As you increase pressures and continue to use the brass, clearances are reduced. Eventually you will hit a point where the shoulder may bear hard into the shoulder which usually makes chambering difficult. BR shooters avoid this situation since it generally causes flyers. Normally they size or bump the shoulder so the bolt will just smoothly close on the loaded round and not disturb the gun in the bags. They may bump the shoulder, they may bump the shoulder and case head (as with a Harrell die) or they may bump the shoulder and size the body (in a custom die) to achieve this goal. They make sure all the cases chamber with the same force. Size too much and you will shorten brass life due to overworking.
BR shooters shoot for minimal or zero headspace while using a min. spec. reamer. This is easiest on brass and probably enhances safety. They generally go one step further and they go for fitted necks where the neck of the casing needs to be turned in order for the casing to fit into the chamber... a whole different story.
Factory chambers are intended to fall into a industry range. To keep costs down a maximum sized chambering reamer is used. As it (reamer) wears the tool would be reground to restore cutting edges and service life to the tool. Over time, the regrind operation will cause the reamer to hit a minimum specification - smallest reamer size. Chambers cut with this reamer are the easiest on brass and offer the tightest fit as per industry standards. Once the reamer is past this min spec it is considered scrap. Most shooters are tickled pink when they have a small chamber. The hole point is to keep the casing as aligned with the bore as possible and a oversize or max spec. chamber increases the misalignment. Reloading can help reduce the affect pending how much of the case you resize. Custom rifle builders often stick with min spec reamers despite the added tooling cost.
I would look else where for your problem. I.E. barrel, bedding, mounts, scope. If you have a spare scope, that is sometimes a quick and easy check!
Joe
Last edited:
Just so I can lay this headspace issue to rest can anyone tell me if I should be concerned about a headspace of 1.626. It is 2 thou short of field(1.638) I have read that at field the gun should not be shot anymore because it would be dangerous. I plan on keeping this rifle for a long time and put many rounds through it so should I rechamber it now or wait until it gets worse?
How do I go about checking throat length? I just assumed it would be ok considering the low round count but I guess I should check it anyway. I always like to learn new things and don't mind buying tools as long as I will get some use out of them. Thanks.
How do I go about checking throat length? I just assumed it would be ok considering the low round count but I guess I should check it anyway. I always like to learn new things and don't mind buying tools as long as I will get some use out of them. Thanks.
I haven't noticed anything being said about the actual wear in the barrel......
It is used, it may be worn enough that it will not shoot any better....
Headspace has very little to do with accuracy at this point, the throat does.
I suggest getting it to a good "smith" for a check over and opinion.... trying to fix this on the internet isn't going to do it....
It is used, it may be worn enough that it will not shoot any better....
Headspace has very little to do with accuracy at this point, the throat does.
I suggest getting it to a good "smith" for a check over and opinion.... trying to fix this on the internet isn't going to do it....
Interesting... I tried using my "other" bolt which headspaced 1.634 (nogo). Actually it will not close on nogo so I guess it is 1.633. Anyway, tried the "other" bolt as a last resort and to my surprise the rifle shot about 1/2 moa with Federal Gold Medal Match ammo. Shooting at 200m the 168gr shot at about 1" and the 175gr shot 3 shots well under 1" and one shot just outside 1". The flier was probably shooter error.
I understand that headspace should not affect accuracy too much but at some point headspace will make a difference wouldn't it? If I were somehow able to safely fire .308 ammo in a 30-06 rifle I doubt that I will ever get it to shoot accurately correct?
Should I buy a new bolt for this rifle or get the chamber recut. Any more info would be greatly appreciated.
Btw, I thank everyone for their posts. There was quite a bit of good information already given. Thanks guys.
I understand that headspace should not affect accuracy too much but at some point headspace will make a difference wouldn't it? If I were somehow able to safely fire .308 ammo in a 30-06 rifle I doubt that I will ever get it to shoot accurately correct?
Should I buy a new bolt for this rifle or get the chamber recut. Any more info would be greatly appreciated.
Btw, I thank everyone for their posts. There was quite a bit of good information already given. Thanks guys.
If a bolt locks up properly, you do not replace it! Headspace adjustment is done via the barrel. Any of several good smiths on this board could take your rifle and run the barrel in one turn of the thread (a roughly 1/10th in), they would then reface the barrel if necessary to fit it to the bolt and rechamber to a nice head space. This also has the advantage of taking the throat out further into your barrel. If your barrel has not been shortened from the chamber end already, this may welll be your best otion around tightening up the headspace. Once you are using your own once fired brass, though, that brass is headspaced correctly for the rifle that it was fired in. The only concerns, as others have stated, are concentricity, and if the headspace really was on the long side, case thinning ahead of the web. Thinning is detected positively by sectioning a few fired cases.
If you do not feel safe with the rifle as is, pay a smith to look at it. This is why they get to charge for their services, they KNOW what they are doing!
If you do not feel safe with the rifle as is, pay a smith to look at it. This is why they get to charge for their services, they KNOW what they are doing!
