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Forum Index > Precision long range hunting and shooting > Remington Sendero Chamber Issues

Remington Sendero Chamber Issues

13 May 2013
@ 06:33 am (GMT)

joshua sutcliffe

Hi Nathan,

After being a long time reader or your forums i have found the wealth of information on TBR invaluable. Thank you!

The reading here also helped me decide to the purchase a Remington Sendero SFII in 7mm Rem Mag. I have installed a Nightforce NSX 5.5-22 x 50 MOAR in nightforce rings and rail and am ok with accuracy now that the crown has been recut and action bedded.
1/2 MOA with 72.5gn of AR2217 162 AMAX@ 86 COAL,
My measured Max COAL is 86.6mm is this a short throat?

From the first firing of the rifle it has been difficult to eject a spent cases, the bolt will lift without any hassle but the rearward pull it sometimes so tight i really have to use 100% strength to open the bolt. After 80 factory rounds through it every case has a small gouge in it as seen here,



also about 10% also come out with this mark,



I have used 0000 steel wool around a bore brush turning with a drill for a total of 5 mins in the chamber and i still get tight bolt pull and the gouge is still present. I also loaded back down to 68gn of AR2217 with still a sticking bolt so am confident the load is not the issue.

The best i can guess is the chamber finish is the issue.
Has anyone else experienced this issue before.
I am thinking i will have to re-chamber?

Replies

1
13 May 2013
@ 04:53 pm (GMT)

Nathan Foster

Re: Remington Sendero Chamber Issues
Hi Joshua, that definitely needs rechambering. What a shame, I have had such a good run with the Sendero's. Your rifle makes a total of two dud chambers for the last few months that I have heard of. Nevertheless, these things happen, it is quite easy to have a reamer create a burr.

86.6mm is about mid range for Remington. Sendero chambers range from around 87.8 to 86.3 max COAL with the A-Max.

Please get the rifle back to the Remington Agent, they will fix this free of charge, though it will cost you as far as wasted ammo and having to start over with load work. Your rifle is a high end model so it is up to Remington to ensure that you receive a high end product. They will be happy to do this.

Please do not use steel wool in the future because of the risk of mild steel contamination on stainless.

If you decide to take the rifle back to the smith who did the recrown for speed of turn-around, please make sure that Remington are still informed so that word can be sent back to Remington U.S. Whichever way you go, I would have someone check locking lug contact while they are at it.

Worst case, ream to 7mm Practical for kicks.
14 May 2013
@ 07:26 am (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Thanks for the hasty reply Nathan,

I contacted the dealer where i purchased the firearm from who then contacted Raytrade here in Aus today and they said to send it back in, So i have pulled down the rifle today and will get it sent off ASAP with the fired cases, il let you know how it goes.

I checked Lug contact tonight with marker pen then worked the bolt a dozen times, this is what i got



Full contact on the ejection side lug and no contact on the other side... thats precision machining :)



I guess i should go ahead and get them lapped on if the chamber issue is resolved?

Regards

Josh
14 May 2013
@ 06:50 pm (GMT)

Nathan Foster

Re: Remington Sendero Chamber Issues
I thought this could go one of two ways. Either the burr was a genuine mistake, or the job was done in a lax manner by a lazy operator- hence why I wanted the lugs checked. Now that you have checked the lugs, I think we have our answer as to the hows and whys.

Best to have the Rem Rep smith lap the lugs before the new barrel is fitted, will avoid increasing head space.
14 May 2013
@ 11:00 pm (GMT)

Martin Taylor

Re: Remington Sendero Chamber Issues
Hi Guys,

This is the 4th Rem with chamber/barrel issues l have heard of in the last 5/6mths here in Aust!
2, 5R Mil spec 308's with mis-aligined cambers and a SPS with a delaminated barrel, I really hope this is not a trend! As l want to purchase the same model Sendero later this year!
15 May 2013
@ 03:51 am (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Hi Martin,

Yes it's a bit a a shame, this is actually my second model 700 with issues, fool me once shame on you fool me twice shame on me! As the saying goes.

You may be interested to know that when ordering this rifle I talked to a person at Raytrade who informed me that Remington were stopping production of the Sendero and I had a bit of trouble getting this one. First they told me that they wernt bringing anymore in so I ordered the Remington law enforcement Police model, which you can get in 7mm mag although it doesn't state it the calibre options, it does in the long text here
http://www.remingtonle.com/rifles/700p.htm

To be honest I was juggling between Sendero and custom in hindsight may have been better of with a custom for the additional money.
Time will tell.

Has anyone else heard of Remington stopping production of the Sendero?
15 May 2013
@ 05:27 am (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Also the brochure I saw said the 700 P comes with the 40x trigger (not sure if this is any better than the xmark) and " each model 700P consistently shoots sub MOA in our factory"

http://www.remingtonle.com/news/catalog.htm

I wouldnt try to hold them to it on accuracy but at least any chamber/barrel issues may be found before leaving the factory and rectified.
15 May 2013
@ 05:02 pm (GMT)

Nathan Foster

Re: Remington Sendero Chamber Issues
Hi guys, I think it is important to make sure these rifles go back to the importer. The more pressure is put on the importer, the more acid is put on the manufacturer to resolve problems. In doing this, we can hopefully get back to the typically good performance of the high end Remington's without these occasional flawed jobs.

As far as custom rifles go Joshua, you have your base for a future custom rifle. Allow the Importer to rectify problems, shoot the barrel till its poked, then rebarrel and make it your ideal rig.

We have to be realistic about all of this. I have a job on the go at the moment, the client has dropped off two rifles. The first rifle is a factory gun that I am to trick it up for him. The second rifle is a semi custom rifle that has allready had the works done by another smith (I usually avoid this type of situation but decided to let it go through with the other job). All I have been asked to do is perform load work for the second rifle. Well, in a nut shell, its a piece of s---t. Its not the smiths fault, its just a very poor barrel from a major U.S custom brand. Groups about the same as 00 buckshot. What I am trying to say here, is that problems can occur whichever way we go. Many of you will have studied this in the long range book, what can happen, how to deal with it, how to work towards success.

The 40x trigger is much better than the X-Pro.
22 Jun 2013
@ 03:18 am (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Hi Nathan,

Received the Sendero back from Remington 1 week ago.
They were quite helpful and polished the chamber, although dubious as to wether this would have solved the issue, i have fired approximately 40 full pressure loads since and the extraction is butter smooth, Happy days!

I went ahead and lapped the lugs and now have 100% contact on one and about 80% on the other i feel this is enough? It took about 175 bolt manipulations to complete.

Thanks again for your helpful advice.

Also i have since found an accurate load, however i have never seen such an affect just by seating depth variation especially away from the lands. The photo below is 72.5gr of AR2217 (H1000) both groups are shot at 200YDS the only difference is the top group is seated at 86mm COAL (0.5mm from lands) and the bottom is 85.3mm COAL (1.2mm from lands).


My question is have you seen this before and can you tell me why this may be?

I have tested the load out to 460YDS and it is still good for 2" groups.
22 Jun 2013
@ 06:58 pm (GMT)

Nathan Foster

Re: Remington Sendero Chamber Issues
Hi Joshua, yes I have seen this before.

What you are dealing with is barrel whip (harmonics). By seating from .5 to 1.2mm jump, you changed "when" the bullet left the barrel. You would think that differing velocities would be enough to alter timing, but this is sometimes not enough to effect meaningful changes in behavior.

You will often see the term "accuracy node" used to describe a sweet spot. In essence, what is occuring, is that the barrel is vibrating in a very uniform way at 1.2mm.

I use the analogy of a baseball pitcher. We tend to see barrels as being rock solid and unmovable. But at a microscopic level, the barrel is indeed throwing the bullet to a very small extent. As you know, if the baseball pitcher does not duplicate his arm movement with each throw- or does not release the ball at the same moment with each throw, there will be a great deal of dispersion at the batter. The pitcher practices to gain muscle memory for repeatable performance. In the rifle barrel, we experiment with both velocity and at times- bullet jump.

One method of working up an accurate load (Berger website) suggests utilizing a single powder charge weight and experimenting with seating depth as a primary variable. To be honest, I find this method to be somewhat shot sighted as a point of advice. Many folk shoot long throated rifles with short bearing surface bullets. The .308 and 155-168 grain bullets is a prime example. So my advice is to experiment with powder charge weights first, then experiment with seating depths if need be.

Whichever way we go, it can be trial. One can easily chalk up a high round count if a rifle does not play ball. In a worst case scenario, where no trends appear, it is possible to arrive at a situation where a full range of incremental charges may need to be employed with three to four different seating depths. If we did this with your rifle, it may look like this:

Three shot groups:
70
70.5
71
71.5
72
72.5
73
73.5

Thats 24 shots. Then we do this with three different seating depths if the rifle showed absolutely no trends- we don't want to accuse the barrel maker of giving us a dud.

3x24= 72

In this example, lets assume that we found a potential sweet spot after all of this work. It then pays to work around the sweet spot in .2 grain increments to see what will happen, how changes will effect ES, what we can expect if we don't weigh a charge perfectly. Some folk will try .1gr increments but lets say .2gr for this example.

Sweet spot was 72.5 grains.
Test:
72.3
72.5 (Seeking confirmation)
72.7.

Round count is now 81. We have not included barrel break in rounds so lets throw in a figure of 20 rounds to get the Sendero to settle. 30 rounds would be better to provide fireformed brass. Plus we have to include foulers for the other sessions. Round count is now up around 115 rounds.

So when you think about it- you did very well to get that level of accuracy in the space of time that you have had the rifle.

22 Jun 2013
@ 07:49 pm (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Thanks for an in-depth explanation Nathan.

To be honest i had a fair idea of the powder charge before i sent the rifle away, just had to make sure it was still the same after chamber polishing. I used information mostly from discussions with yourself and Jim Moseley, so thanks again.

Unfortunately we are struggling to get AMAXs here at the moment in Tasmania so iv had to switch to Burger 168gn VLDs but was lucky enough to find an accurate load just touching the lands behind 73gn of AR2217 however there were some pressure signs at this charge so iv have loaded up a few more at 72.7, if this proves to retain accuracy i will then follow the Burger recommendations on seating depth as you have suggested. Will let you know how it goes.
29 Jun 2013
@ 10:22 am (GMT)

joshua sutcliffe

Re: Remington Sendero Chamber Issues
Hi Nathan,

Just an update regarding the Burger VLDs, Dropped back to 72.7 with still slight pressure signs and a loss of accuracy.
Dropped to 72.5 and experimented with seating depth.
Into lands 0.25mm 0.5 MOA @ 200 yds
away from lands 0.25mm 2 MOA
away from lands 1.2mm 0.6 MOA
away from lands 2.3mm 2 MOA
away from lands 3.3mm 2.5 MOA

Amaxs turned up a couple of days ago so will put VLDs on the back burner.
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