Problems with Remington 700

07 October 2002, 13:05

In 1985 I bought a Remington 700 in .270 Win. The rifle was bought used. When I first got it, it would not shoot worth a damn. After scrubbing out the bore for several days I got it to shoot about 1.75 inch groups@100yds. After working up some hand loads for it I got it to shoot dime size groups sometimes and quarter size groups all the time. The load that worked the best for me was 52 grains of IMR 4350 a Winchester LR primer and a 150 grain Nosler Ballistic Tip. The load never showed any signs of excess pressure in that rifle.

Last week I loaded up some ammo using that same load and went to the rifle range. Firing through my chronograph the bullets averaged 2950 fps. and the groups were at 2.5 inches. That same load used to average 2700 fps. Upon inspection of the cases I found that the primers were cratered and I measured the web area just ahead of the extracter groove and it measured .466 On new never fired brass that same measurement is .4635 . That seems like a lot of expansion. Also if I rechamber a fired round the bolt closes with high resistance. Why is a load that used to be safe in my rifle now showing signs of high pressure?

07 October 2002, 13:25

<Big Stick>

My guess would be a different lot of powder(slightly faster burning rate,than your prior lot) or a different lot of brass,that is of less internal capacity(weigh that brass,to get an idea).............

07 October 2002, 14:02

kraky

Quickload says in a 23" barrel that load should make 2828 fps at 57k psi. So, I'm at a loss to explain why it was so mild before and a little warm now. Those ballistic tips to have alot of surface area compared to say a hornady so I can see that they might run just a little warmer than some other 150 grainers.

It might be a powder lot situation or, has your powder gotten a little old and lost some of it's consistancy?? A change in primer could also account for maybe 100 fps. OR a hot day with ammo in the sun can make a difference to. This is all I can think of off the top of my head.

08 October 2002, 10:18

Hot Core

quote:
Originally posted by Turkeyshooter:
1. ...the bullets averaged 2950 fps. and the groups were at 2.5 inches. That same load used to average 2700 fps.

2. Upon inspection of the cases I found that the primers were cratered and I measured the web area just ahead of the extracter groove and it measured .466 On new never fired brass that same measurement is .4635 . That seems like a lot of expansion.

3. Also if I rechamber a fired round the bolt closes with high resistance. Why is a load that used to be safe in my rifle now showing signs of high pressure?

Hey Turkeyshooter, Definitely looks like HIGH pressure to me too.

1. That seems to be a considerable difference in the Velocity. Just as you, I'd consider that indicates something is different and creating HIGH Pressure with the new Loads.

2. I consider a cratered primer a high Pressure sign too.

But, most of the cases I load for in this casehead size have a Pressure Ring Expansion(PRE) above those numbers. And some of my chambers are SAAMI Minimum. Those last two statements can be misleading to you though.

It would be a good idea to buy one box of factory ammo, shoot them, average the PRE and use it as a Standard. Then redevelop your Loads in those same exact cases and when you get to the same "Average" PRE - STOP.

If you are trying to take these measurements with a 0.001" capable Caliper, then you are not using the proper tool for the task. Hopefully you are using 0.0001" capable Micrometers. On your 270Win cases, locate the "widest diameter" on the fired casebody (Pressure Ring) forward of the Extraction Groove. Then rotate the Pressure Ring between the anvils of the Micrometer until you locate the "high spot". Be careful not to force the case as you turn it, or you will skew the results. Use the highest value that will keep the case from slipping out from between the anvils as the PRE.

3. This indicates to me that you "might" have somehow ended up with some 0.284"/7mm bullets getting stuck in the 0.277" bullet box by accident. Check the diameter of the remaining Loaded Bullets (as well as the ones in the box) to see what they measure. Also, since they are B-Tips, the color should be different from the 0.277" B-Tips if in fact they are 0.284". If you have the wrong color B-Tips stuck in the end of the bullets, Nosler would sure be interested in seeing some of them and the box they came in.

Another possibility is the bullets somehow managed to get seated too far out and are jamed against the Lands. That is still a lot of Pressure to result from this alone though.

If you opened a new box of bullets, the "Ogive" might be shaped slightly different. Each time you open a new box of bullets, it is a good idea to recheck the Seating Depth for those new bullets.

Check to see if a bullet will slide into the mouth of a "Fired Case" easily. If not, then the necks might be too thick.

Last but not certainly not least, if you are "NOT" trimming your cases, the previous firings of those cases and subsequent resizings might have stretched the cases enough that the edge of the casemouth is jamed into the end of the chamber. This will cause the case to "pinch" the bullet and create high pressure like you are seeing or even higher.

Best of luck to you.

08 October 2002, 16:15

claybuster

Welcome to the club Turkeyshooter! It could be something simple as the ammo temp..I bought a m1a in the fall,,,,spent half the winter developing that "sweet load" for it.It did really good in march,april,may,and june.Then,in july,on a rather hot day that I was shooting on,,,I damn near blew my head off.And yes the ammo was fairly hot to the touch.I've since then,given up winter time load development.You've been shooting the gun for 17 years,and it sounds like you've been handloading it for a good while,Try to think back,,,New lot of powder?,new brass?,primers?,temps.? I kind of discard the wrong bullet size in the box thing.Good Luck.Hope you figure it out!

08 October 2002, 18:02

<Dan in Wa>

Are you still cleaning the barrel real clean?
Nosler BT's leave alot more copper in my barrels than most conventional bullets. With some semi-rough factory barrels, I have to clean after 10/15 shots to maintain accuracy. Just a thought.

09 October 2002, 01:30

<green 788>

I'm going to have to agree with Hotcore on this one...

It's probably the brass--either not trimmed to length, as he says, or the case necks are thicker than those on the brass you initially used.

If you have any of those rounds that haven't been fired, take one apart and weigh the powder charge. It's possible that a scale or powder measure malfunction was the culprit.

When I'm dealing with max charges, I always weigh every charge.

You should pick up a box of the Winchester factory "power point" Super X 130 grain ammo from Walmart. It's 11 dollars a box, and it's incredibly accurate you will find. Two Ruger 77's, two Winchester model 70's (a pre and a post 64), and one Remington 700 I'm familiar with will all shoot this load extremely well. It's worth a try in your 270.

I have always felt that the 270 was at its best with 130 grain bullets. If you're hunting elk, or other such large game, I can understand you wanting the heavier bullet. O'Conner recommended the 150's for elk, if I recall correctly. But O'Conner didn't have today's bullets, either. Most folks who have tried the 130 grain partitions have reported good results on elk sized game. 55 grains of the IMR 4350 with the 130 grain bullet should shoot well in most 270's.

Let us know what you find out. Take one of those rounds apart and weigh the charge...

Dan Newberry
green 788

11 October 2002, 09:45

Turkeyshooter

Just to update. Hot core, my chamber length was measured at 2.580..I usally trim the neck .020 shorter than that. To touch the lands with that brand of bullet, the OAL must be 3.490...I seat them at 3.470 . Dan, Yes I still keep the barrel clean and Green, the reason I shoot 150 grain bullets is that it never would shoot 130 grainers worth a damn. Two days ago I loaded some more rounds cutting back to 49 grains of 4350 and after fire forming the brass I rechambered the fired round and the bolt still closed with more resistance than it should. SOMETHING IS NOT RIGHT HERE!! So to solve the problem I went out and bought a new Remington 700 BDL in .270 .......now if I can just keep my wife from finding out...shhhhh!!

[ 10-11-2002, 00:48: Message edited by: Turkeyshooter ]