Do my howas have extremely long throats

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Do my howas have extremely long throats

Post by Kelsey Cooter » 20 Jan 2019, 7:32 pm

When I started reloading I noticed my howa stainless sporter barreled 223 had a longer throat then my wife's ruger precision 223. At the time I was only loading for the ruger so didn't think to much about it.

But now I'm loading super roo's for the howa.
The distance to the lands with the super roo's is 1.956" measured to the ogive.
At the moment I'm seating the projectiles at 1.860" to the ogive which gives me a COL of 2.240.
Magazine length isn't a drama but I felt like I didn't want the projectile any further out after reading that you want the projectile seated at least .223 into the neck. But that gives me pretty much 100thou of jump?

Then I bought my howa blued varmint 308 and have discovered the same thing. With 150gr seirra gamekings the distance to the lands is 2.298 measured to the ogive.
The COL in the ADI book is 2.703 which gives me 2.130 to the ogive.

What do you blokes think of this and just how far out is to far out when seating?
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Re: Do my howas have extremely long throats

Post by SCJ429 » 20 Jan 2019, 8:17 pm

You need enough of the pill in the neck so it stay straight when presented to the lands. How does it shoot with 100 thou jump? Most 223 shooting lighter projectiles have a fair bit of jump but still shoot OK. The 223 neck is fairly short and I would seat it with bullet contacting all of that neck or close to it.
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Re: Do my howas have extremely long throats

Post by Kelsey Cooter » 20 Jan 2019, 8:35 pm

SCJ429 wrote:You need enough of the pill in the neck so it stay straight when presented to the lands. How does it shoot with 100 thou jump? Most 223 shooting lighter projectiles have a fair bit of jump but still shoot OK. The 223 neck is fairly short and I would seat it with bullet contacting all of that neck or close to it.


I've got it shooting around 3/4moa at 100m at the moment. I'd like to get it down to half moa. With the osa blitzkings it as always shot about the same, and they are even further from the lands
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Re: Do my howas have extremely long throats

Post by marksman » 20 Jan 2019, 9:33 pm

sometimes the factory throats have a giant jump because of the twist so you can use heavy projectiles that are longer
I have found using a tangent ogive type bullet can help to get closer to the lands eg speer
if I cannot get to the lands without at least the diameter of the projectile in the case I will jump it at mag length, my 22-250 has a 4mm jump and shoots dots but I have to reload with no runout at all, I also think as long as the projectile is still in the case as it is starting in the lands it should stay straight as it goes up the bore
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Re: Do my howas have extremely long throats

Post by Stix » 20 Jan 2019, 10:54 pm

Hry Kelsey...im sorry to butt in here...but i have one of those silly overthinking questions...

So i have 3 x 22-250's that all have different chamber measurements.

Im mostly talking about the 2 measurements i can easily measure...they are caae head to shoulder datum, & case head to ogive (where ogive contacts rifling).
Can also measure the case body dismeterat various points .
Edit... :lol: ...thats meant to read "dimensions at"... :lol: (typing with one thumb on a mobile)

Generally speaking, i would have thought that the rifle with the "loosest" barrel (largest diameter) & largest body measurement would easily be the rifle to be able to take the most pressure...
My figuring being it would clearly have the most free volume to burn the same smount of powder, thus having less pressure build up.

It so happens thst my old shot out 788 has the largest chamber measurements, & the loosest bore, yet can take less pressure than 2 new Sako factory made barrels that are notably tighter in every measurement.
Infact all factory ammo is far too hot for it, & it starts to hit max at a very moderate 36gr of 2208 pushing the average 50gr BT...

The largest of the 2 Sako factory chamberings can go 37gr with 55's. (Albeit eith different brass so not a 'true comparison).

Infact of the 2 Sako factory chambered rifles, the one with the shortest base to shoulder measurement appears to be able to take the higher powder charge before primers start to loose their radius. ..& that is with same brand & almost identical weight brass....(admitadely not volume tested).

I have very loose understanding that the lead &/or throat area plays a part in being a section of the "combustion chamber", thus can play a significsnt role in pressure with some cartridges, so given i can't measure this section (without letting cases grow to excessive length), is it likely this area of the chambers in question are vastly different in the rifles...?
Or...
Is this just normal & indicative of the old adage that states "every barrel is different" boiling down to even the metalurgy of any given barrel being a factor in the ballistics...?
, or...
is there more to it that im missing &/or dont understand...?

Im not sure if im being clear in how im asking the question...& i know it makes no difference to how things are...but its something ive often thought of & so figured this thread is as close a lead into asking my silly question...dorry if its a bit long winded... :unknown:
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Re: Do my howas have extremely long throats

Post by Kelsey Cooter » 21 Jan 2019, 9:07 pm

Stix wrote:Hry Kelsey...im sorry to butt in here...but i have one of those silly overthinking questions...

So i have 3 x 22-250's that all have different chamber measurements.

Im mostly talking about the 2 measurements i can easily measure...they are caae head to shoulder datum, & case head to ogive (where ogive contacts rifling).
Can also measure the case body dismeterat various points .
Edit... :lol: ...thats meant to read "dimensions at"... :lol: (typing with one thumb on a mobile)

Generally speaking, i would have thought that the rifle with the "loosest" barrel (largest diameter) & largest body measurement would easily be the rifle to be able to take the most pressure...
My figuring being it would clearly have the most free volume to burn the same smount of powder, thus having less pressure build up.

It so happens thst my old shot out 788 has the largest chamber measurements, & the loosest bore, yet can take less pressure than 2 new Sako factory made barrels that are notably tighter in every measurement.
Infact all factory ammo is far too hot for it, & it starts to hit max at a very moderate 36gr of 2208 pushing the average 50gr BT...

The largest of the 2 Sako factory chamberings can go 37gr with 55's. (Albeit eith different brass so not a 'true comparison).

Infact of the 2 Sako factory chambered rifles, the one with the shortest base to shoulder measurement appears to be able to take the higher powder charge before primers start to loose their radius. ..& that is with same brand & almost identical weight brass....(admitadely not volume tested).

I have very loose understanding that the lead &/or throat area plays a part in being a section of the "combustion chamber", thus can play a significsnt role in pressure with some cartridges, so given i can't measure this section (without letting cases grow to excessive length), is it likely this area of the chambers in question are vastly different in the rifles...?
Or...
Is this just normal & indicative of the old adage that states "every barrel is different" boiling down to even the metalurgy of any given barrel being a factor in the ballistics...?
, or...
is there more to it that im missing &/or dont understand...?

Im not sure if im being clear in how im asking the question...& i know it makes no difference to how things are...but its something ive often thought of & so figured this thread is as close a lead into asking my silly question...dorry if its a bit long winded... :unknown:
:drinks:


I was hoping someone would give their thoughts on this as I definately can't offer much, as far as measuring that section, would a lead cast give you an accurate measurement? Before I made this thread I was actually doing a bit of reading about rifle throats and found lots of write ups where they had used lead casts of chambers to measure the throat length
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Re: Do my howas have extremely long throats

Post by Rod_outbak » 21 Jan 2019, 10:32 pm

Kesley,

Messing around with the seating depth on my Howa 1500 Stainless Sporter .223.
The rifle is about 600 rounds old(September 2018).
I'd previously been loading .223 for our old 788, and while the new rifle seems to digest the rounds loaded for the 788, I'd prefer to get the seating depth dialled in to suit the Howa.

So, tonight, I got the chance to follow the advice of someone here on this forum, and measured maximum cartridge length, by using a cleaning rod down the barrel.
[After I figured out I needed to remove the bloody firing pin out of the bolt...]
So, difference between the bolt face and the tip of a Z-Max projectile sitting in the start of the rifling, turns out to be 2.280"
So, I'm seating to a COL (measured to tip, and not the ogive) of 2.260"
So, that gives me about 0.020" jump to the rifling(not exact due to variations in the tip, but close enough for hunting loads).

Happy with that.

I dont know if this will help you, but I'd suggest doing same to see if you do have an excessively long throat.

Cheers,

Rod.
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Re: Do my howas have extremely long throats

Post by Kelsey Cooter » 22 Jan 2019, 5:41 am

Rod_outbak wrote:Kesley,

Messing around with the seating depth on my Howa 1500 Stainless Sporter .223.
The rifle is about 600 rounds old(September 2018).
I'd previously been loading .223 for our old 788, and while the new rifle seems to digest the rounds loaded for the 788, I'd prefer to get the seating depth dialled in to suit the Howa.

So, tonight, I got the chance to follow the advice of someone here on this forum, and measured maximum cartridge length, by using a cleaning rod down the barrel.
[After I figured out I needed to remove the bloody firing pin out of the bolt...]
So, difference between the bolt face and the tip of a Z-Max projectile sitting in the start of the rifling, turns out to be 2.280"
So, I'm seating to a COL (measured to tip, and not the ogive) of 2.260"
So, that gives me about 0.020" jump to the rifling(not exact due to variations in the tip, but close enough for hunting loads).

Happy with that.

I dont know if this will help you, but I'd suggest doing same to see if you do have an excessively long throat.

Cheers,

Rod.


Cheers Rod, I use the hornady OAL gauge and hornady comparator to measure my rifles, do you think using the method you've used will give a different result?
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Re: Do my howas have extremely long throats

Post by marksman » 22 Jan 2019, 11:13 am

1) Generally speaking, i would have thought that the rifle with the "loosest" barrel (largest diameter) & largest body measurement would easily be the rifle to be able to take the most pressure...
My figuring being it would clearly have the most free volume to burn the same smount of powder, thus having less pressure build up.?

no you can still only load to the same pressure, a looser diameter would only mean it would take more powder to get there

2) It so happens thst my old shot out 788 has the largest chamber measurements, & the loosest bore, yet can take less pressure than 2 new Sako factory made barrels that are notably tighter in every measurement.
Infact all factory ammo is far too hot for it, & it starts to hit max at a very moderate 36gr of 2208 pushing the average 50gr BT...

it's more about action design, the 788 is a rear locker making it a weaker design that will stretch under pressure more because of back thrust

I think this may help with your questions Stix :thumbsup:

http://www.rifleshootermag.com/editoria ... 0806/84354

http://www.bergerbullets.com/effects-of ... to-part-1/
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Re: Do my howas have extremely long throats

Post by Rod_outbak » 22 Jan 2019, 1:40 pm

Kesley,

I havent used the Hornady OAL gauge to say for certain, but what I have read suggests it will be more accurate than the method I'm using.
For one thing, I'm measuring the total length of the cartridge, wheras you are measuring to the ogive.
Your method has less variation; mine will vary from the slight difference in the tips of the projectiles.

I just thought it might give you some sort of idea as to what your Howa is doing.
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Re: Do my howas have extremely long throats

Post by Stix » 23 Jan 2019, 5:49 am

Thanks
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Re: Do my howas have extremely long throats

Post by bigfellascott » 23 Jan 2019, 1:13 pm

Kelsey Cooter wrote:
SCJ429 wrote:You need enough of the pill in the neck so it stay straight when presented to the lands. How does it shoot with 100 thou jump? Most 223 shooting lighter projectiles have a fair bit of jump but still shoot OK. The 223 neck is fairly short and I would seat it with bullet contacting all of that neck or close to it.


I've got it shooting around 3/4moa at 100m at the moment. I'd like to get it down to half moa. With the osa blitzkings it as always shot about the same, and they are even further from the lands


Nothing wrong with those results Kelsey, what stock have you got them in out of interest?
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Re: Do my howas have extremely long throats

Post by Kelsey Cooter » 23 Jan 2019, 8:40 pm

The 223 is just in the timber howa stock and the 308 is in the bell and carlson, I've bedded the 308.
I bloody love the set up of the 223, it just feels perfect. Weights a bloody tonne though.
I find it interesting that, that timber stock has a purpose made spot that contacts the barrel, where as if you buy the same barrelled action with any other stock it's freefloated...
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Re: Do my howas have extremely long throats

Post by bigfellascott » 23 Jan 2019, 10:35 pm

I reckon I'd free float the barrel if it was mine.
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