.308 Cold Bore vs. Warm Bore issues

.308 Cold Bore vs. Warm Bore issues

This is a discussion on .308 Cold Bore vs. Warm Bore issues within the Rifles forums, part of the Sniping Related category; Hey guys, I'd first like to state that I'm entirely new to long distance shooting and I joined this forum to access the vast knowledge ...

Page 1 of 2 12 LastLast
Results 1 to 10 of 18
Like Tree9Likes

Thread: .308 Cold Bore vs. Warm Bore issues

  1. #1
    Junior Member
    Join Date
    Jan 2017
    Location
    Western New York unfortunately
    Posts
    4

    .308 Cold Bore vs. Warm Bore issues

    Hey guys, I'd first like to state that I'm entirely new to long distance shooting and I joined this forum to access the vast knowledge of you fine gentleman. That being said, I'm not entirely new to marksmanship.

    Now that I have that out of the way, I'd like to mention that it is to my understanding that the first couple of rounds POI through a cold bore are going to be off zero until the bore is warm.

    A couple of month ago, I bought a Remington 700 SPS .308 that was never fired before with a Burris mtac 4.5-14x42mm optic, a bipod, a sling, reloading dyes, and 80 rounds all for $600. I COULD NOT pass that up. The barrel is 26", heavy bore with a 1 in 10 twist.

    So now down to the real issue. The past couple of times I have been to the range, I would shoot cold bore at 100 yards and could hold a 2" group with 3 rounds (I know that not good in terms with most of you guys, I'm still learning). I would then shoot at 200 yards and hold a 3.5" group with 3 rounds. However, after I had put about 10-15 rounds down range, my rounds POI would be almost random at either distance. The ammo used was relatively cheap as I'm a full time college student and that's really all I can afford. The ammo was Perfecta .308 147 grain jacketed.

    With my understanding of cold bore shots, shouldn't I be less accurate the first couple of rounds and not the opposite? Is this a possibility of zeroing the rifle with cold bore shots, cheap ammo, or both? Could cold temperatures also affect the temperature of the bore as well?

  2. #2
    Super Moderator NorCalFocus's Avatar
    Join Date
    Jul 2013
    Location
    Surprise, AZ
    Posts
    3,758
    Usally a cold bore, is one, maybe two shots, thats it. What it means is you shoot the cold bore and as the barrel warms your POI matches your POA, not that the groups are small.

    Your not having real cold bore issues here. Until you have the skill and gear to shoot constant MOA or less groups, don't worry about cold bore. Once you have the skills and equipment, you can then start cold bore tacking. Meaning you track where and how many shots it take for your barrel to warm up. This is done over lots of ranges trips. Your building an average.

    You need better ammo. Cheap ammo will give you cheap results. That ammo won't shoot 1 MOA and with that your not learning anything from the shots fired.

    What stock in on that Remington you have?
    jake3ekaj likes this.
    I redefined trust between my wife and I. Bought her a gun, hand loaded ammo for it, showed her how to shoot it, and made her the beneficiary on my life insurance.

    -Chris

    Hidden Content Originally Posted by sns2 Hidden Content
    I got my gun today. Went to the range. You guys weren't kidding. Even off a rest it seemed to be touching the barrel. What an utter piece of s*** that Hogue stock is.

  3. #3
    Senior Member Gunguy308's Avatar
    Join Date
    Sep 2015
    Location
    Phoenix Arizona
    Posts
    457
    If it's in a factory plastic stock, look to change it. I have a 700 sps varmint as well and it loves Federal Gold medal Match 175gr, either the .308 or the 7.62x51 stuff.

    Rem 700p .308 26"
    Vortex Gen 2 4.5-27x56 EBR-2C Mrad
    HS Precision stock
    Rem 700sps Tac .308 20"
    Magpul Hunter 700 with DBM
    Waiting on optics
    Rem 700sps .308 26"
    Vortex Gen 2 4.5-27x56 EBR-2C Mrad
    BC A3 stock with Wyatte DBM
    jake3ekaj likes this.

  4. #4
    Senior Member ddd oo7's Avatar
    Join Date
    Mar 2011
    Location
    Memphis, TN
    Posts
    4,186
    I highly doubt you have a 1:10 twist 26" heavy barreled remington...but you could. Most of them are 1:12 twist. You might have a 20" 1:10 twist barrel though.

    If a rifle is built right by a good smith...and it is bedded properly...and everything is right the cold bore will shift very little to none. If your cold bore is shifting a lot then you have a secondary problem that needs to be sorted out.

    Now...several things will be contributing to the issues you noted.

    First...147gr ammo of any type is not match grade ammo and will not shoot as such. 2" at 100 is probably the limits of the ammo in that rifle. 147 gr ammo is intended to spray and pray through machine guns. Most SPS-V's like 175smk's as well as anything...so you might try to find some of those and shoot them to see how they do.

    Second...while the sps-V is a "heavy barrel", it is a light "heavy barrel". Mine was capable of about 8 shots before groups started opening up and by 15 shots the groups were over twice the size as when I started shooting. The barrel needs time to cool in order to maintain accuracy.

    Third...The stock on the SPS-V is not a floating stock. It contacts the barrel from the factory and is designed that way. If you want to shoot groups that are under 1" at 100 you will need a different stock.

    Fourth...Shooter fatigue can also play into opening up groups. My best group of the day is usually the second one I shoot. It takes me one group to get settled into the rifle...and the second group is great...then concentration and patience begins to fail and groups start to suffer. I have gotten better with this the more I shoot...but it is still there and as a new shooter very likely will be coming into play as well.
    jake3ekaj likes this.
    Desert Tech SRS with TS 308 conversion
    TacOps Tac 51 .260 on Surgeon action
    NRA Life-Member

    Hidden Content

  5. #5
    Senior Member
    Join Date
    Oct 2006
    Location
    Austin, Texas
    Posts
    1,622
    You may have a different issue: clean bore <syndrome>.

    If you clean a bore down to the metal, it takes 2-5 rounds to season up the bore so it shoots right.
    Once seasoned, the bore can then be cold or warm (or technically hot; but we don't shoot fast enough to see this often.)

    So there are three conditions:: Clean Cold bore (CCB), Cold Bore (CB), and Warm Bore (WB).
    You set zero based on the WB PoI, and then keep notes on where the CCB and where the CB PoIs are (they are likely different, each.)
    Also note, CCB, and CB offsets from zero are different with different ammo.

    So the first thing one needs to do is lay in a supply of quality ammo.
    Being able to shoot 3+ boxes of cheap ammo (instead of 1 box of good stuff) will do you no/little good in developing the skills needed to do precision shooting.

  6. #6
    Senior Member Hypo's Avatar
    Join Date
    Feb 2014
    Location
    GA
    Posts
    1,339
    Welcome and congratulations on getting a decent deal for an entry level set up.
    Don't get discouraged like it appears the previous owner did.
    This is a lifetime hobby. As long as you take care of the equipment, only your skills will rust through lack of use.
    Just give yourself of budget of both time and money and you will make steady progress.
    It takes both time and money.
    You can't buy skill.
    Just be sure to purchase good equipment that will not hold you back.

    Like the others said, ammo, stock and maybe a trigger upgrade.
    Then you will want a shooting mat and maybe a spotting scope to save trips downrange looking at targets.
    Get a reloading press and some measuring tools and a scale and stick to one gun for the time being.

    Read the sticky posts here.
    This one First.
    Nate's response covers it all.

    Rifle modifications that increase accuracy the most?
    jake3ekaj likes this.

  7. #7
    Senior Member gpark09's Avatar
    Join Date
    Sep 2015
    Location
    Los Angeles, CA
    Posts
    492
    I agree with what others mostly said about the ammo may being a problem. Your initial shots landed where you intended. That kinda took a way bore temp problem. Well.... unless your stock is a one of those cheap synthetic plastic which may be in contact with your bore after it heats up.

    If you are wondering about the why ammo would affect the POI, it's the jacket. Clean the bore thoroughly and give it a try with reputable ammo. If can't afford big name premium match ammo, try Fiocchi match. They are lower than other premium match ammo.

  8. #8
    Member landtoy80's Avatar
    Join Date
    Jan 2015
    Posts
    78
    Check the stock screws for proper torque or at least tightness if you dont have torque wrench. Same with scope mounts.

    I had a Mosin Nagant that patterned like a shotgun. After getting even pressure on barrel, it shot a lot better. Sounds like the barrel is making contact with stock as it warms up.
    Sounds like the stock is not free floating, wonder if there is a way to make it free floating? (Google, search)
    Can you run a dollar bill between the stock and barrel when cold up and down the length of barrel? Free-Float-Barrel-Dollar-Bill-Gunsamerica-1024x697.jpg
    Try it when barrel is warm and see if can move freely in same spots.

    Shoot more than 3 round groups.

    Is the bipod on stock or barrel? Try removing it and shoot from sand bags.

    Are you cleaning the bore after every session? If you don't go long periods between shooting sessions, try not cleaning the bore. This will end the Clean Cold bore issue.
    It is becoming more common to not clean the bore till accuracy fall off. (Google search)
    Last edited by landtoy80; 01-05-2017 at 08:31 PM.
    jake3ekaj likes this.

  9. #9
    Senior Member ddd oo7's Avatar
    Join Date
    Mar 2011
    Location
    Memphis, TN
    Posts
    4,186
    If the rifle is a sps-v and it is in the factory stock then it is not free floating at all. The sps-v had two little plastic bumps that are in contact with the barrel at all times. They make it appear to float...but it doesn't. Hot/cold doesn't matter.
    Desert Tech SRS with TS 308 conversion
    TacOps Tac 51 .260 on Surgeon action
    NRA Life-Member

    Hidden Content

  10. #10
    Junior Member maddogmaglin's Avatar
    Join Date
    Oct 2016
    Posts
    7
    One thing that was not mentioned here is dry firing. When I get to the range and get set up, I dry fire my rifle 3 or 4 times while I carefully focus on my scope reticle watching for the slightest movement. Usually after one to 2 dry firings I find myself settling down to where I can pull the trigger without any movement showing up in my scope. This, along with MINIMAL rifle bore maintenance, and good ammo, will produce sub MOA cold bore groups from my 700P almost every time.
    jake3ekaj likes this.

Page 1 of 2 12 LastLast

Ads

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Similar Threads

  1. Replies: 22
    Last Post: 06-21-2010, 08:04 PM
  2. Cold bore
    By WT101 in forum Introductions
    Replies: 1
    Last Post: 05-03-2008, 06:37 AM
  3. Replies: 11
    Last Post: 10-16-2007, 09:42 AM
  4. WOW!!!! 762 yards cold bore .308
    By tattoo414 in forum Rifles
    Replies: 3
    Last Post: 07-20-2007, 01:16 PM
  5. The cold-bore shot
    By norwegian_sniper in forum SOP
    Replies: 4
    Last Post: 05-29-2007, 08:50 PM