Home Forums Reloading Varmint Rifles Your Experience/Opinion

Does any one want to give your similiar experience, ( or opinion) on the following?

I have put 1244 rounds thru the following barrel, a Pac-Nor, SSSM, for my Ruger #1, Rem 6mm. I have used H-4831, H-4350, H-4895, Varget, & R-19, using Hornady 75 gr. V-Max, & Barnes 85 gr. XLC�s.

Today, I measured, using my Stony Point gauge, & Sinclair comparator gauge, for the Hornady 75 gr. V-Max, & the OAL was, 3.474.

I usually measure 10 bullets, & take the average.

When it was new, I had done the same measurements, & the OAL was 3.445

So it looks like the throat moved .029


For the Barnes 85 gr. XLC, I had measured 3.445, & today it measured 3.468, or a

a difference of .023.

Now I understand these measurements could be a little off, because of me, etc., but I use a fairly good digital gauge for measuring, & I try to be as consistent as I can be on measuring..

My questions are:

1) is .029 , or .023 a lot of throat wear for 1244 rds. ?

2) what opinion ( would rather have facts) is there, say, in 1244 rds, it moved .029, in 5000 rounds, would it move approx. 5 times that or approx. .145 ?

3) Is .145 a lot of throat wear ?

4) I intend to go thru the same �drill� with my 06�s, & 223�s. Just wondered if any one had done some thing similar, & what were your results.

I also understand that "shooting hot", fast & hot loads will move it faster. I don't shoot either.

Thanks

I don't have the answers, but would like to hear what the others say. I am interested......

You will never get 5000 rounds out of a 6MM or a .243.....

On one hand, it's nice to keep track of your round count and/ or
your throat movement. But.....
In reality, it's more like your tires or your gas gauge.
The first half lasts longer than the second half.
In all my competition guns, I seat my bullets to get a square mark on my bullet.
Eventually, you still may be able to touch the lands, but the competive accuracy is gone.
So, it will all come down to your accuracy requirements, more so
than throat movement or loss.

I realise that 5000 is not a good #, for a Rem 6mm, or 243.

that was just a #, I picked out of the air, could be 1500,or 2500.

my interest, is is .029 a reasonable # for 1244 rounds ?

I also understand if you hot rod a barrel, depending on caliber, it could be 500 rounds.

I guess the question should have been, normally, in 22 & 6mm calibers, how much throat wear does one see in 500, 1000, 2000, etc. rounds.

Do people who shoot a lot of competation, or who are gun smiths, look at a throat, & see the wear is .050, or .145, & say time for a new barrel.

Maybe I should ask this on a benchrest forum, to see when they change there barrels, after the throat has moved ?????

aalf

not to dispute your experience, questions just because of my own ignorance.

why does the first half last longer than the last half ?

"Eventually, you still may be able to touch the lands, but the competive accuracy is gone".

can you explain to me why, since you can still touch the lands.


on your competation guns, do you keep seating to the lands, until you can't seat any longer, & then rebarrel ?

You gotta remember, without a borescope to see, you're just measuring throat movement, but the wear and heat checking is extending further down the bore also.
Just because you can still touch the lands, doesn't mean it will still shoot.
There's no set "rule" on throat loss, just what shows up on the target.
Your accuracy requirements is what matters.
For a prairie dog gun, if it starts at a 1/2", gradually it's
5/8", then 3/4" and so on. If you miss, no big deal, shoot again.
Now, on, let's say my Hunter gun, trying to hit the 1/16" dot in
the middle of the 10 ring. After maybe 2000rds, it gets tougher to keep them in the 10 ring, let alone hitting the dot.
Time for a new barrel regardless of where the throat is, even though I can still touch the lands.
Clear as mud?

Unless accuracy is going to pot, I wouldn't worry about it.. after accuracy is sliding, I have found changing powder and load can still produce an accurate rifle even if it has a worn throat...

Still have my first 243 and have more than 5000rds down the tube. Doesn't shoot as good as it used to but will still shoot under moa. I think more is attributed to how you put the rds down the tube. HAPPY HUNTING

a bore scope is something I don't have, or access to . would love to have one, as I 'm sure it would keep me busy.

hadn't thougth about "but the wear and heat checking is extending further down the bore also".

I was thinking that most of the wear/erision would be in the throat area.

thanks for the comments

Did you use the same bullet for each measurement? Or did you use the same brand/weight bullet but from a different lot? Rick.

Chestsprings: For such an in depth and interesting posting/question you forgot to include ONE very important thing - HOW is the Rifle shooting now as compared to previously - better, worse or the same???
If you think you can stop barrel/throat erosion - I have news for you - we can't stop it! We CAN observe differences in or changes in accuracy - have you observed this?
Some Rifles in 6mm Remington (and I have owned a bunch of them but am down to three right now) do start showing a slight diminishment of accuracy at 900 to 1,200 rounds down range.
This is not unusual.
I have gotten 3,000 rounds out of one of my 6mm's and I am still happy with it's accuracy.
I don't keep track of the throat erosion in as quantifiable way as you have done though so I can't compare directly for you.
I love my Sinclair Bullet Seating Depth Tool for finding the O.A.L. of my test loads, but after I decide on a "length" (where accuracy is good) I leave the Sinclair Tool alone.
I hope your accuracy is still holding up for you - I wonder if the reason you DID recently take this new measurement is because of diminshing accuracy - I hope not!
I wish to take a W.A.G. here on your question #2 - my W.A.G. is that the throat erosion will not stick to a strict formula of progression (X = Y, then 5X = 5Y). I would think that after nearly 5 times the ammo down the barrel that the throat erosion would probably double in length maybe triple?
Best of luck with that 6mm in the future!
Hold into the wind
VarmintGuy

I have a 243 with a high mileage barrel on it, got it used so I am not sure how many rounds have been down it....but groups were getting to the point I was thinking of a rebarrel...

however, a load of 25 grains of SR 4759 with 80 grain bullets turn in groups still less than half a minute of angle... so I just changed to shooting that.. and let it keep on trucking...

It likes 20 grains of Blue Dot with almost any bullet and also 30 grains of RL 7 and IMR 4198 with almost any bullet also...

If you redline the MV with H 414 with about any heavier bullet, it likes those also...

This is opposed to groups like 2 to 2 1/2 inches at 100 yds, with the typical 4350 loads....

Gene,
It depends on what kind of accuracy you are willing to accept.
You will notice that you are missing shots at long range when you know the hold was good. It might go all of a sudden but I am betting it will get worse over a long period.
If you talk to the guys on the highpower rifle board you might find out that accuracy life is about 2,000 rounds? (for a 243)
Depending on cleaning techniques and how hot you let the barrel get when shooting.
My 25-06 barrel lasted 3,000 rounds in a prairie dog town.
I shot fast and let it get real hot somedays but that is why I bought it.
It eventually got to the point that it was only good for close range shooting and I can't stand a 14 pound rifle for that purpose.
I have the same gauge but the only thing that matters to me is how well they shoot. Only you can decide when it is time to rebarrel.
whelennut

Every One,

I'm sorry if my post's indicated I was having accuracy problems. Not yet.

please excuse some of the pictures, as I am not very good with taking pictures

It's about throat/ wear. really wanted to know if some others had noticed how much "erosion" of the throat, they had after a certain amount of rounds.

the following pictures will show some groups I shot with the rifle, at 100 yds. over a few ys. these were shot off a plastic fold up table ( I don't have access to a bench) & a metal folding chair.

all groups are at 100 yds.

picture #1 is the rifle


picture #2 is a three shot gp. I shot on 9-6-99 , after I had the rifle a few weeks. had put 56 rds. thru it.


picture #3 is a three shot gp., Barnes 95 X, on 4-19-00, after I had 110 rds. thru it.


picture #4 is a three shot gp., Hornady 75 gr. V-Max, on 4-22-01, after 193 rds. thru it.


picture #5, is a three shot group Hormnady 75 gr. V-Max, on 1-19-06, after 954 rds thru it.


picture #6, is a five shot gp., Hornady 75 gr. V-Max, on 6-26-06


as you can see, no accuracy problems, yet.

today, if I can get into the field of a horse farm that lets me shoot,( we had a lot of rain) I intend to shoot a 5 shot group with the 75gr. V-Max' with the old OAL of back in 1999, & 5 shots with the new OAL where it moved .029

I can't wait to see the group after 2,500 rounds.
Speaking of throat erosion, after 2,300 rounds through my Ruger #1 in 220 Swift, I can seat the 55 gr Speer out as far as it will go and I still can't touch the rifling.
It will still hold MOA at 100 yds. (For now anway.)
I am hoping to make it to 3,000 rds. Then I'm shopping for a new barrel.
whelennut