June 16, 2015, 01:35 PM | #1 |
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Case trim .308 Win
So I have got into the habit of trimming my .308 brass to 2.005 after each sizing. My question is, should I let them grow to max before trimming? What affect would it have on the accuracy. Would longer brass support the bullet better if I'm loading closer to the lands?
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June 16, 2015, 01:39 PM | #2 |
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What are you shooting it out of? If you are not an elite benchrester, you're not going to be able to see a difference.
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June 16, 2015, 01:44 PM | #3 |
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I am shooting rem 700P, 26 in bbl, mostly off bench or prone. This one is my range toy, accuracy is the goal.
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June 16, 2015, 05:31 PM | #4 |
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Nice, 700P is an accurate rifle for sure but it is not a bench rifle. BartB once posted that you may see 1/20th of an inch improvement if you keep all your brass at the exact same OAL.
I shoot a Savage Precision Carbine, my son a R700 MilSpec and we can't tell any difference regardless of if I'm using brass I trimmed or brass that all were under spec. |
June 16, 2015, 06:36 PM | #5 |
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My question is more to, 2.005" as trim. Is 2.006" to 2.014" (+1 trim -1 max) acceptable? Given that all cases are the same trim length. Any pro - con to length?
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June 17, 2015, 08:37 AM | #6 |
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I think so, that is how I do my lots now. I lock the calipers in at 2.015" and measure the batch, if any of them are long the entire batch gets trimmed down to 2.005".
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June 17, 2015, 09:15 AM | #7 | |
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I have a chamber that allows for cases that are longer from the mouth of the case to the case head by .016", I could trim to match 'trim to' case length but that would result in a case that does not cover my chamber. And, that is what I want, I want a case to cover all of the chamber. F. Guffey |
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June 17, 2015, 08:05 PM | #8 |
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From what I've ben reading on this forum I seem to see a pattern in your answers guffey. It seems to be mostly about measuring ones particular chamber from bolt face to lands and everything in between. Would a chamber casting be a good way to measure all of it? Not to be sarcastic, but my calipers don't fit in my chamber. I Have a lot to learn yet, and I appreciate all the info this forum provides to new loaders like myself.
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June 17, 2015, 09:19 PM | #9 |
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I trim every loading. Everything the same length, everything consistant, everything same as last time I loaded. Get the same results each time to the range. anneal every 4th load. You want to be consistant every load. Same shoulder bump,same neck tension, same seating depth.You find a load that shoots great in your rifle-Keep loading that load exact every time. Just makes sense.
Now if Bart chimes in ( smart guy). he will talk about throat erosion, which I have no doubt is real. I have well over 3000 rounds down my match 308 rifle and to this day, still seat every load the same as I did 2 years ago and still get same results on target. If the day comes that my groups start to get out of control , a new barrel will be ordered. And then the game starts all over to find the perfect load. I have 9 rifles now and I have one load for each of them. I do not mess with 2 or 3 different loads for each rifle. One load per rifle. Same bullet, trim length,primer,powder and seating depth.
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June 17, 2015, 10:27 PM | #10 | ||
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Chamber casting? I do not find it necessary to case a chamber, again, I form cases, the 308 W chamber is shorter than the 30/06 chamber from the shoulder to the bolt face by .388". With .388" I can not miss. I make chamber castings, there is a lot of work involved and different. F. Guffey |
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June 18, 2015, 09:16 AM | #11 |
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Then there is changing the attitude of reloaders, there are modifications that can be made to adept tools for other purposes. That is not easy to talk about on a reloading forum, I am of the opinion reloaders are investors in companies that are manufacturers of reloading equipment.
There are at least three ways to determine the length of a chamber without a head space gage. F. Guffey |
June 18, 2015, 09:43 AM | #12 |
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0.01" of case neck isn't going to make any practical difference supporting the bullet.
The reason for trimming cases is to keep them from extending into the part of the bore where there is no clearance for the case to expand and release the bullet (which creates high, possibly dangerous pressure). The only other reason to trim brass is for uniformity. And that only matters really matters when crimping. If you are trimming after every firing, I think you are overdoing it.
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June 19, 2015, 12:21 AM | #13 |
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This is kind of a long winded story to get to a point...
I once saw a youtube video of a guy sporting custom thousand dollar rifles, checking the bores with an 800 dollar bore scope with video attachment, showing his Dillon reloading presses. I was impressed until he took his handloads to the range, ran them through his thousand dollar rifles, and came back with 5 moa groups.... He was convinced he was a great hand loader and shooter, but I remain skeptical. So if you are trimming every reload, and it's working for you, by all means stick with it. If you stop trimming every time I expect you won't see a difference with a 700P, but sometimes having a ritual for reloading does more for the trigger nut than anything else. Jimro
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June 19, 2015, 05:19 AM | #14 |
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Trimming everytime is probebly not a requierment, but it does keep everything the same from shot to shot. 44AMp- It has nothing to do with bullet hold or support. It has to do with each bullet being the same as the last. Does it make a difference- According to you-no, but then thats according to you. Each to there own I guess. I like to know when I dont hit the bullseye- It was operator error that caused it.
The top Bench shooters I talk to do it, they also anneal every round. They do this for a reason. They have found out IT does make a difference. I do not aspire to be a good shooter I want to be a great shooter, and that is why I do it. I shoot about 300 to 500 rounds a week and continue to get better and better. I put my faith in what the top shooters do over what You and I and a few others think. I became a member of this forum for 1 reason that has turned into 2 reasons. First was to learn from all the great members in here and second to help others with what I can. Through the years now my posts have changed from what I thought I knew to what I know now. I have now Had Bart on an occasion have people private e mail me for info and advice also. I take that as a very large compliment. In the end- I am here for the same reason you are-To learn and teach. I tell things that have taken me from a MOA shooter to a sub MOA shooter. While 70% of my shooting is 300 yards I still get out once a month and stretch it to 1000 to 1400 yards.
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NRA Certified RSO NwCP- Performance Isn't Optional Last edited by 4runnerman; June 19, 2015 at 05:51 AM. |
June 19, 2015, 07:39 AM | #15 | ||
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Quote:
Quote:
F. Guffey Last edited by F. Guffey; June 19, 2015 at 09:10 AM. Reason: change case to cast |
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June 19, 2015, 12:08 PM | #16 |
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Guffy- I also said I have NO DOUBT it's true- However so far in 3000 plus rounds it has not made a difference on my accuracy that i get from the rifle.
I still seat to the same depth as I did when the rifle was new. I also do not worry nor care about throat erosion, as when the groups open up-I buy a new barrel. I buy one a year for my 6BR. I find one load that shoots great and that is what I shoot always. Barrels are a expendable item. I have never found a need for all the gauges you have. I have the Hornady gauge to measure my seating depth to the lands and that is all I need. I do not need to measure throat erosion- I buy a new barrel. Don't need 90% of the tools you have Guffy. I load , I shoot, I load , I shoot, when things go South-I buy a new Barrel and go back to loading and shooting. You seem to have tool for everything- What has it gained you?. Answer-Nothing other than Money and the ability to measure a shot barrel. Heck I do that for free just by watching my groups. Got well over 15,000 rounds down my 223-Still shooting the same bullet,same powder, same AOL I started with 5 years ago. Still pulling the same accuracy. Do I have throat erosion-Yes. Has it made a difference-NO. With all your tools and stuff you do Guffy- Do you even have time to shoot any more?. I bet you have a tool to measure everything.
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NRA Certified RSO NwCP- Performance Isn't Optional Last edited by 4runnerman; June 19, 2015 at 12:16 PM. |
June 19, 2015, 12:28 PM | #17 |
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I'm sure Mr. Guffy has a lot of experience and much to offer, but I usually can only understand 25% of his posts (not total posts, but 25% of each post )...
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June 19, 2015, 12:39 PM | #18 | |
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Then there are design functions of tools used by reloaders. Most reloaders measure the length of a case from the end of the neck to the case head. F. Guffey |
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June 19, 2015, 12:53 PM | #19 |
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I simply run my .308's through an RCBS trim die every time after sizing and I know they are consistent. One simple step for me and it seems to have the desired effect.
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June 19, 2015, 01:18 PM | #20 |
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Guffy- Case length is a given. Shoulder bump is what is important. Which again-You do not need a tool to determine
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June 19, 2015, 03:04 PM | #21 |
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Started out with a Rem. 700 LTR 308 20" HB, It's a smaller version of the 700P. I trim every reload to 2.010 keep the head space to .001 Shooting 168 gr.HPBT Sierra bullet over 40.5 gr. of IMR 4064 in a F/C or ADI Case both are thicker the most brass. Win & Rem. brass I would be 1. grain higher on my loads. I agree with 4runnerman on his case prep.
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June 19, 2015, 03:14 PM | #22 |
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Old Stoney, the trim die is the most accurate way to trim cases. Again, the 308 W form/trim die is my favorite forming die, next is the 243 W forming die.
F. Guffey |
June 19, 2015, 03:31 PM | #23 | |||
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If you are going to be selective about trimming, that is only trim once in a while, you must measure all cases and make no assumptions that just because all the cases you measured are under max, the rest of the cases will also be under max. This is not so in my experience. The odd ball long case pops up. Quote:
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June 19, 2015, 07:16 PM | #24 | |
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F. Guffey |
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June 20, 2015, 11:18 AM | #25 |
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F. Guffey, I'm with You
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